#include <bits/stdc++.h>
#include <cassert>
using namespace std;
using ll = long long int;
using u64 = unsigned long long;
using pll = pair<ll, ll>;
// #include <atcoder/all>
// using namespace atcoder;
#define REP(i, a, b) for (ll i = (a); i < (b); i++)
#define REPrev(i, a, b) for (ll i = (a); i >= (b); i--)
#define ALL(coll) (coll).begin(), (coll).end()
#define SIZE(v) ((ll)((v).size()))
#define REPOUT(i, a, b, exp, sep) REP(i, (a), (b)) cout << (exp) << (i + 1 == (b) ? "" : (sep)); cout << "\n"

// @@ !! LIM(debug cmpNaive perm)

// ---- inserted function f:<< from util.cc

// declarations

template <typename T1, typename T2>
ostream& operator<< (ostream& os, const pair<T1,T2>& p);

template <typename T1, typename T2, typename T3>
ostream& operator<< (ostream& os, const tuple<T1,T2,T3>& t);

template <typename T1, typename T2, typename T3, typename T4>
ostream& operator<< (ostream& os, const tuple<T1,T2,T3,T4>& t);

template <typename T1, typename T2, typename T3, typename T4, typename T5>
ostream& operator<< (ostream& os, const tuple<T1,T2,T3,T4,T5>& t);

template <typename T1, typename T2, typename T3, typename T4, typename T5, typename T6>
ostream& operator<< (ostream& os, const tuple<T1,T2,T3,T4,T5,T6>& t);

template <typename T>
ostream& operator<< (ostream& os, const vector<T>& v);

template <typename T, typename C>
ostream& operator<< (ostream& os, const set<T, C>& v);

template <typename T, typename C>
ostream& operator<< (ostream& os, const unordered_set<T, C>& v);

template <typename T, typename C>
ostream& operator<< (ostream& os, const multiset<T, C>& v);

template <typename T1, typename T2, typename C>
ostream& operator<< (ostream& os, const map<T1, T2, C>& mp);

template <typename T1, typename T2, typename C>
ostream& operator<< (ostream& os, const unordered_map<T1, T2, C>& mp);

template <typename T, typename T2>
ostream& operator<< (ostream& os, const queue<T, T2>& orig);

template <typename T, typename T2>
ostream& operator<< (ostream& os, const deque<T, T2>& orig);

template <typename T, typename T2, typename T3>
ostream& operator<< (ostream& os, const priority_queue<T, T2, T3>& orig);

template <typename T>
ostream& operator<< (ostream& os, const stack<T>& st);

#if __cplusplus >= 201703L
template <typename T>
ostream& operator<< (ostream& os, const optional<T>& t);
#endif

ostream& operator<< (ostream& os, int8_t x);

ostream& operator<< (ostream& os, const __int128& x);

// definitions

template <typename T1, typename T2>
ostream& operator<< (ostream& os, const pair<T1,T2>& p) {
  os << "(" << p.first << ", " << p.second << ")";
  return os;
}

template <typename T1, typename T2, typename T3>
ostream& operator<< (ostream& os, const tuple<T1,T2,T3>& t) {
  os << "(" << get<0>(t) << ", " << get<1>(t)
     << ", " << get<2>(t) << ")";
  return os;
}

template <typename T1, typename T2, typename T3, typename T4>
ostream& operator<< (ostream& os, const tuple<T1,T2,T3,T4>& t) {
  os << "(" << get<0>(t) << ", " << get<1>(t)
     << ", " << get<2>(t) << ", " << get<3>(t) << ")";
  return os;
}

template <typename T1, typename T2, typename T3, typename T4, typename T5>
ostream& operator<< (ostream& os, const tuple<T1,T2,T3,T4,T5>& t) {
  os << "(" << get<0>(t) << ", " << get<1>(t)
     << ", " << get<2>(t) << ", " << get<3>(t) << ", " << get<4>(t) << ")";
  return os;
}

template <typename T1, typename T2, typename T3, typename T4, typename T5, typename T6>
ostream& operator<< (ostream& os, const tuple<T1,T2,T3,T4,T5,T6>& t) {
  os << "(" << get<0>(t) << ", " << get<1>(t)
     << ", " << get<2>(t) << ", " << get<3>(t) << ", " << get<4>(t) << ", " << get<5>(t) << ")";
  return os;
}

template <typename T>
ostream& operator<< (ostream& os, const vector<T>& v) {
  os << '[';
  for (auto it = v.begin(); it != v.end(); it++) {
    if (it != v.begin()) os << ", ";
    os << *it;
  }
  os << ']';

  return os;
}

template <typename T, typename C>
ostream& operator<< (ostream& os, const set<T, C>& v) {
  os << '{';
  for (auto it = v.begin(); it != v.end(); it++) {
    if (it != v.begin()) os << ", ";
    os << *it;
  }
  os << '}';

  return os;
}

template <typename T, typename C>
ostream& operator<< (ostream& os, const unordered_set<T, C>& v) {
  os << '{';
  for (auto it = v.begin(); it != v.end(); it++) {
    if (it != v.begin()) os << ", ";
    os << *it;
  }
  os << '}';

  return os;
}

template <typename T, typename C>
ostream& operator<< (ostream& os, const multiset<T, C>& v) {
  os << '{';
  for (auto it = v.begin(); it != v.end(); it++) {
    if (it != v.begin()) os << ", ";
    os << *it;
  }
  os << '}';

  return os;
}

template <typename T1, typename T2, typename C>
ostream& operator<< (ostream& os, const map<T1, T2, C>& mp) {
  os << '[';
  for (auto it = mp.begin(); it != mp.end(); it++) {
    if (it != mp.begin()) os << ", ";
    os << it->first << ": " << it->second;
  }
  os << ']';

  return os;
}

template <typename T1, typename T2, typename C>
ostream& operator<< (ostream& os, const unordered_map<T1, T2, C>& mp) {
  os << '[';
  for (auto it = mp.begin(); it != mp.end(); it++) {
    if (it != mp.begin()) os << ", ";
    os << it->first << ": " << it->second;
  }
  os << ']';

  return os;
}

template <typename T, typename T2>
ostream& operator<< (ostream& os, const queue<T, T2>& orig) {
  queue<T, T2> que(orig);
  bool first = true;
  os << '[';
  while (!que.empty()) {
    T x = que.front(); que.pop();
    if (!first) os << ", ";
    os << x;
    first = false;
  }
  return os << ']';
}

template <typename T, typename T2>
ostream& operator<< (ostream& os, const deque<T, T2>& orig) {
  deque<T, T2> que(orig);
  bool first = true;
  os << '[';
  while (!que.empty()) {
    T x = que.front(); que.pop_front();
    if (!first) os << ", ";
    os << x;
    first = false;
  }
  return os << ']';
}

template <typename T, typename T2, typename T3>
ostream& operator<< (ostream& os, const priority_queue<T, T2, T3>& orig) {
  priority_queue<T, T2, T3> pq(orig);
  bool first = true;
  os << '[';
  while (!pq.empty()) {
    T x = pq.top(); pq.pop();
    if (!first) os << ", ";
    os << x;
    first = false;
  }
  return os << ']';
}

template <typename T>
ostream& operator<< (ostream& os, const stack<T>& st) {
  stack<T> tmp(st);
  os << '[';
  bool first = true;
  while (!tmp.empty()) {
    T& t = tmp.top();
    if (first) first = false;
    else os << ", ";
    os << t;
    tmp.pop();
  }
  os << ']';
  return os;
}

#if __cplusplus >= 201703L
template <typename T>
ostream& operator<< (ostream& os, const optional<T>& t) {
  if (t.has_value()) os << "v(" << t.value() << ")";
  else               os << "nullopt";
  return os;
}
#endif

ostream& operator<< (ostream& os, int8_t x) {
  os << (int32_t)x;
  return os;
}

// for Enum type; just displays ordinals.
template <typename E>
typename std::enable_if<std::is_enum<E>::value, std::ostream&>::type
operator<<(std::ostream& os, E e) {
    return os << static_cast<typename std::underlying_type<E>::type>(e);
}

// This is a very ad-hoc implementation...
ostream& operator<<(ostream& os, const __int128& v) {
  unsigned __int128 a = v < 0 ? -v : v;
  ll i = 0;
  string s(64, ' ');
  if (v == 0) {
    s[i++] = '0';
  }else {
    while (a > 0) {
      s[i++] = '0' + (char)(a % 10);
      a /= 10;
    }
  }
  if (v < 0) {
    s[i++] = '-';
  }
  s.erase(s.begin() + i, s.end());
  reverse(s.begin(), s.end());
  os << s;
  return os;
}


// ---- end f:<<

// ---- inserted library file debug.cc
template <class... Args>
string dbgFormat(const char* fmt, Args... args) {
  size_t len = snprintf(nullptr, 0, fmt, args...);
  char buf[len + 1];
  snprintf(buf, len + 1, fmt, args...);
  return string(buf);
}

template <class Head>
void dbgLog(bool with_nl, Head&& head) {
  cerr << head;
  if (with_nl) cerr << endl;
}

template <class Head, class... Tail>
void dbgLog(bool with_nl, Head&& head, Tail&&... tail)
{
  cerr << head << " ";
  dbgLog(with_nl, forward<Tail>(tail)...);
}

#if DEBUG
  #define DLOG(...)        dbgLog(true, __VA_ARGS__)
  #define DLOGNNL(...)     dbgLog(false, __VA_ARGS__)
  #define DFMT(...)        cerr << dbgFormat(__VA_ARGS__) << endl
  #define DCALL(func, ...) func(__VA_ARGS__)
#else
  #define DLOG(...)
  #define DLOGNNL(...)
  #define DFMT(...)
  #define DCALL(func, ...)
#endif

/*
#if DEBUG_LIB
  #define DLOG_LIB(...)        dbgLog(true, __VA_ARGS__)
  #define DLOGNNL_LIB(...)     dbgLog(false, __VA_ARGS__)
  #define DFMT_LIB(...)        cerr << dbgFormat(__VA_ARGS__) << endl
  #define DCALL_LIB(func, ...) func(__VA_ARGS__)
#else
  #define DLOG_LIB(...)
  #define DFMT_LIB(...)
  #define DCALL_LIB(func, ...)
#endif
*/

#define DUP1(E1)       #E1 "=", E1
#define DUP2(E1,E2)    DUP1(E1), DUP1(E2)
#define DUP3(E1,...)   DUP1(E1), DUP2(__VA_ARGS__)
#define DUP4(E1,...)   DUP1(E1), DUP3(__VA_ARGS__)
#define DUP5(E1,...)   DUP1(E1), DUP4(__VA_ARGS__)
#define DUP6(E1,...)   DUP1(E1), DUP5(__VA_ARGS__)
#define DUP7(E1,...)   DUP1(E1), DUP6(__VA_ARGS__)
#define DUP8(E1,...)   DUP1(E1), DUP7(__VA_ARGS__)
#define DUP9(E1,...)   DUP1(E1), DUP8(__VA_ARGS__)
#define DUP10(E1,...)   DUP1(E1), DUP9(__VA_ARGS__)
#define DUP11(E1,...)   DUP1(E1), DUP10(__VA_ARGS__)
#define DUP12(E1,...)   DUP1(E1), DUP11(__VA_ARGS__)
#define GET_MACRO(_1,_2,_3,_4,_5,_6,_7,_8,_9,_10,_11,_12,NAME,...) NAME
#define DUP(...)          GET_MACRO(__VA_ARGS__, DUP12, DUP11, DUP10, DUP9, DUP8, DUP7, DUP6, DUP5, DUP4, DUP3, DUP2, DUP1)(__VA_ARGS__)
#define DLOGK(...)        DLOG(DUP(__VA_ARGS__))
#define DLOGKL(lab, ...)  DLOG(lab, DUP(__VA_ARGS__))

#if DEBUG_LIB
  #define DLOG_LIB   DLOG
  #define DLOGK_LIB  DLOGK
  #define DLOGKL_LIB DLOGKL
#endif

// ---- end debug.cc

// ---- inserted library file cmpNaive.cc

const string end_mark("^__=end=__^");

int naive(istream& cin, ostream& cout);
int body(istream& cin, ostream& cout);

void cmpNaive() {
  while (true) {
    string s;
    getline(cin, s);
    bool run_body;
    if (s.at(0) == 'Q') {
      return;
    }else if (s.at(0) == 'B') {
      run_body = true;
    }else if (s.at(0) == 'N') {
      run_body = false;
    }else {
      cerr << "Unknown body/naive specifier.\n";
      exit(1);
    }
    string input_s;
    while (true) {
      getline(cin, s);
      if (s == end_mark) break;
      input_s += s;
      input_s += "\n";
    }
    stringstream ss_in(move(input_s));
    stringstream ss_out;
    ss_out << setprecision(20);
    if (run_body) {
      body(ss_in, ss_out);
    }else {
      naive(ss_in, ss_out);
    }
    cout << ss_out.str() << end_mark << endl;
  }
}

int main(int argc, char *argv[]) {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  cout << setprecision(20);

#if CMPNAIVE
  if (argc == 2) {
    if (strcmp(argv[1], "cmpNaive") == 0) {
      cmpNaive();
    }else if (strcmp(argv[1], "naive") == 0) {
      naive(cin, cout);
    }else if (strcmp(argv[1], "skip") == 0) {
      exit(0);
    }else {
      cerr << "Unknown argument.\n";
      exit(1);
    }
  }else {
#endif
    body(cin, cout);
#if CMPNAIVE
  }
#endif
  return 0;
}

/*
int naive(istream& cin, ostream& cout) {
  return 0;
}
int body(istream& cin, ostream& cout) {
  return 0;
}
*/

// ---- end cmpNaive.cc

// ---- inserted library file perm.cc

template <bool dup, typename T>
struct IntPermBase {
  int n;
  int r;
  vector<int> vec;
  bool started;
  vector<T> mapping;

  bool start_check() {
    if constexpr (dup) { if (not ((1 <= n and 0 <= r) or (n == 0 and r == 0))) return false; }
    else { if (not (0 <= n and 0 <= r and r <= n)) return false; }
    started = true;
    vec.resize(r, 0);
    return true;
  }

  bool finish() {
    vec.resize(0);
    started = false;
    return false;
  }

  IntPermBase(int n_, int r_) : n(n_), r(r_), started(false) {
    if (n >= 0) {
      mapping = vector<T>(n);
      for (int i = 0; i < n; i++) {
        if constexpr (is_integral<T>::value) mapping[i] = (T)i;
        else mapping[i] = T();
      }
    }
  }
  IntPermBase(int n_, int r_, vector<T> mp) : n(n_), r(r_), started(false), mapping(move(mp)) {
    if (ssize(mapping) != n) throw runtime_error("IntPermBase: incorrect mapping length");
  }

  T at(int i) const { return mapping[vec[i]]; }

  T operator[](int i) const { return at(i); }

  void set_mapping(auto f) {
    for (int i = 0; i < n; i++) mapping[i] = f(i);
  }

  vector<T> vec_view() const {
    vector<T> res;
    for (int i = 0; i < r; i++) res.push_back(mapping[vec[i]]);
    return res;
  }
};

template<typename T = int>
struct IntPerm : IntPermBase<false, T> {
  using Base = IntPermBase<false, T>;
  using Base::vec, Base::r, Base::n, Base::started;

  vector<vector<int>> cands;
  vector<int> cidx;

  bool start_check() {
    if (not IntPermBase<false, T>::start_check()) return false;
    iota(vec.begin(), vec.end(), 0);
    cands.resize(r);
    cidx.resize(r);
    for (int i = 0; i < r; i++) {
      for (int j = n - 1; j >= i; j--) cands[i].push_back(j);
      cidx[i] = n - i - 1;
    }
    return true;
  }

  bool finish() {
    cands.resize(0);
    cidx.resize(0);
    return IntPermBase<false, T>::finish();
  }

  IntPerm(int n_, int r_) : IntPermBase<false, T>(n_, r_) {}
  IntPerm(int n_, int r_, vector<T> mp) : IntPermBase<false, T>(n_, r_, mp) {}

  bool get() {
    if (not started) return start_check();
    int i = r - 1;
    for (; i >= 0 and cidx[i] == 0; i--);
    if (i < 0) return finish();
    vec[i] = cands[i][--cidx[i]];
    for (int j = i + 1; j < r; j++) {
      if (j == i + 1) {
        cands[j].resize(0);
        for (int k = 0; k < (int)cands[i].size(); k++) {
          if (k == cidx[i]) continue;
          cands[j].push_back(cands[i][k]);
        }
      }else {
        cands[j] = cands[j - 1];
        cands[j].pop_back();
      }
      cidx[j] = n - j - 1;
      vec[j] = cands[j][cidx[j]];
    }
    return true;
  }
};

template<typename T = int>
struct IntComb : IntPermBase<false, T> {
  using Base = IntPermBase<false, T>;
  using Base::vec, Base::r, Base::n, Base::started, Base::finish;

  bool start_check() {
    if (not IntPermBase<false, T>::start_check()) return false;
    iota(vec.begin(), vec.end(), 0);
    return true;
  }

  IntComb(int n_, int r_) : IntPermBase<false, T>(n_, r_) {}
  IntComb(int n_, int r_, vector<T> mp) : IntPermBase<false, T>(n_, r_, mp) {}

  bool get() {
    if (not started) return start_check();
    int i = r - 1;
    for (; i >= 0 and vec[i] == n - r + i; i--);
    if (i < 0) return finish();
    vec[i]++;
    for (int j = i + 1; j < r; j++) vec[j] = vec[j - 1] + 1;
    return true;
  }
};

template<typename T = int>
struct IntDupPerm : IntPermBase<true, T> {
  using Base = IntPermBase<true, T>;
  using Base::vec, Base::r, Base::n, Base::started, Base::finish, Base::start_check;

  IntDupPerm(int n_, int r_) : IntPermBase<true, T>(n_, r_) {}
  IntDupPerm(int n_, int r_, vector<T> mp) : IntPermBase<true, T>(n_, r_, mp) {}

  bool get() {
    if (not started) return start_check();
    for (int i = r - 1; i >= 0; vec[i--] = 0) if (++vec[i] < n) return true;
    return finish();
  }
};

template<typename T = int>
struct IntDupComb : IntPermBase<true, T> {
  using Base = IntPermBase<true, T>;
  using Base::vec, Base::r, Base::n, Base::started, Base::finish, Base::start_check;

  IntDupComb(int n_, int r_) : IntPermBase<true, T>(n_, r_) {}
  IntDupComb(int n_, int r_, vector<T> mp) : IntPermBase<true, T>(n_, r_, mp) {}

  bool get() {
    if (not started) return start_check();
    int i = r - 1;
    for (; i >= 0 and vec[i] == n - 1; i--);
    if (i < 0) return finish();
    vec[i]++;
    for (int j = i + 1; j < r; j++) vec[j] = vec[i];
    return true;
  }
};

template<typename INT>
struct IntDirProd {
  vector<INT> lim;
  int r;
  vector<INT> vec;
  bool started;

  IntDirProd(const vector<INT>& lim_) : lim(lim_), r(lim.size()), started(false) {}

  int at(int i) const { return vec[i]; }

  const vector<INT>& vec_view() const { return vec; }

  bool start_check() {
    for (int i = 0; i < r; i++) if (lim[i] == 0) return false;
    started = true;
    vec.resize(r, 0);
    return true;
  }

  bool finish() {
    vec.resize(0);
    started = false;
    return false;
  }

  bool get() {
    if (not started) return start_check();
    for (int i = r - 1; i >= 0; vec[i--] = 0) if (++vec[i] < lim[i]) return true;
    return finish();
  }
};

template<typename INT>
struct IntPartition {
  INT n;
  vector<INT> vec;
  bool started = false;
  IntPartition(INT n_) : n(n_) {}
  
  bool get() {
    if (not started) {
      started = true;
      vec = vector<INT>(n, 1);
      return true;
    }else if (ssize(vec) == 1) {
      started = false;
      return false;
    }else {
      ll b = vec.back(); vec.pop_back();
      ll a = vec.back(); vec.pop_back();
      ll c = a + b;
      ll a1 = a + 1;
      while (c - a1 >= a1) {
        vec.push_back(a1);
        c -= a1;
      }
      vec.push_back(c);
      return true;
    }
  }

  INT at(int i) const { return vec[i]; }
  const vector<INT>& vec_view() const { return vec; }
};

// ---- end perm.cc

// @@ !! LIM -- end mark --

int naive(istream& cin, ostream& cout) {
  ll big = 1e18;
  ll N, Q; cin >> N >> Q;
  string S; cin >> S;
  REP(_q, 0, Q) {
    ll l, r; cin >> l >> r; l--;
    ll len = r - l;
    IntPerm ip(len, len);
    ll ans = big;
    while (ip.get()) {
      ll t = 0;
      REP(i, 0, len) {
        t = 10 * t + '0' + S[l + ip[i]];
      }
      if (t % 8 == 0) {
        ll rnum = 0;
        REP(i, 0, len) REP(j, i + 1, len) if (ip[i] > ip[j]) rnum++;
        ans = min(ans, rnum);
      }
    }
    if (ans == big) ans = -1;
    cout << ans << endl;
  }

  return 0;
}
int body(istream& cin, ostream& cout) {

  ll big = 1e18;
  ll N, Q; cin >> N >> Q;
  string S; cin >> S;
  vector pos(N + 1, vector<ll>(10));
  pos[0] = vector<ll>(10, -1LL);
  REP(i, 0, N) {
    pos[i + 1] = pos[i];
    ll d = S[i] - '0';
    pos[i + 1][d] = i;
  }
  REP(i, 0, Q) {
    ll l, r; cin >> l >> r; l--; 
    if (l + 1 == r) {
      if (S[l] == '8') {
        cout << 0 << "\n";
      }else {
        cout << -1 << "\n";
      }
    }else if (l + 2 == r) {
      ll x = 10 * (S[l] - '0') + 1 * (S[l + 1] - '0');
      ll y = 1 * (S[l] - '0') + 10 * (S[l + 1] - '0');
      ll ans = -1;
      if (x % 8 == 0) ans = 0;
      else if (y % 8 == 0) ans = 1;
      cout << ans << "\n";
    }else {
      ll ans = big;
      REP(xx, 0, 125) {
        ll x = xx * 8;
        auto f = [&]() -> ll {
          ll y2 = (x /   1) % 10;
          ll y1 = (x /  10) % 10;
          ll y0 = (x / 100) % 10;
          ll pos2 = pos[r][y2];
          if (pos2 < l) return big;
          ll pos1;
          if (y1 == y2) pos1 = pos[pos2][y1];
          else          pos1 = pos[r][y1];
          if (pos1 < l) return big;
          ll pos0;
          if (y0 == y1) pos0 = pos[pos1][y0];
          else if (y0 == y2) pos0 = pos[pos2][y0];
          else pos0 = pos[r][y0];
          if (pos0 < l) return big;
          vector<ll> w{pos0, pos1, pos2};
          sort(ALL(w));
          ll ret = (r - 1 - w[2]) + (r - 2 - w[1]) + (r - 3 - w[0]);
          DLOGK(ret);
          ret += (pos0 < pos1 ? 0 : 1) + (pos0 < pos2 ? 0 : 1) + (pos1 < pos2 ? 0 : 1);
          DLOGK(i, l, r, x, pos0, pos1, pos2, ret);
          return ret;
        };
        ans = min(ans, f());
      }
      if (ans == big) ans = -1;
      cout << ans << "\n";
    }
  }

  return 0;
}