#include "atcoder/fenwicktree.hpp"
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;

using isize = size_t;
using i32 = int;
using u32 = unsigned int;
using i64 = long long;
using u64 = unsigned long long;
using i128 = __int128_t;
using u128 = __uint128_t;
using f64 = long double;
using p2 = pair<i64, i64>;
using el = tuple<i64, i64, i64>;
using mint = atcoder::modint998244353;

void _main();
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  _main();
}

i64 pow(i64 x, i64 n) {
  i64 res = 1;
  i64 t = x;
  while (n > 0) {
    if (n & 1) {
      res = res * t;
    }
    t = t * t;
    n >>= 1;
  }
  return res;
}
i64 pow(i64 x, i64 n, i64 m) {
  i64 res = 1;
  i64 t = x % m;
  while (n > 0) {
    if (n & 1) {
      res = res * t % m;
    }
    t = t * t % m;
    n >>= 1;
  }
  return res;
}

void _main() {
  i64 n, q;
  cin >> n >> q;
  string s;
  cin >> s;
  vector<vector<i64>> idx(10);
  for (i64 i = 0; i < n; i++) {
    idx[s[i] - '0'].push_back(i);
  }
  for (;q--;) {
    i64 l, r;
    cin >> l >> r;
    l--;
    if (r - l <= 3) {
      i64 ans = 1e18;
      vector<i64> p;
      for (i64 i = l; i < r; i++) {
        p.push_back(i - l);
      }
      do {
        i64 x = 0;
        for (i64 i = 0; i < p.size(); i++) {
          x = x * 10 + s[p[i]] - '0';
        }
        if (x % 8 != 0) continue;
        atcoder::fenwick_tree<i64> bit(p.size());
        i64 sum = 0;
        for (i64 i = 0; i < p.size(); i++) {
          sum += bit.sum(p[i], p.size());
          bit.add(p[i], 1);
        }
        ans = min(ans, sum);
      } while (next_permutation(p.begin(), p.end()));
      if (ans == 1e18) {
        cout << "-1\n";
      } else {
        cout << ans << "\n";
      }
      continue;
    }
    vector<i64> lim(10, n);
    for (i64 i = 0; i < 10; i++) {
      lim[i] = lower_bound(idx[i].begin(), idx[i].end(), r) - idx[i].begin();
    }
    vector<i64> cnt(10, 0);
    i64 ans = 1e18;
    for (i64 i = 0; i < 1000; i++) {
      if (i % 8 != 0) continue;
      string t = to_string(i);
      if (t.size() != 3) continue;
      bool ok = true;
      vector<p2> v;
      for (i64 j = t.size() - 1; j >= 0; j--) {
        i64 x = t[j] - '0';
        i64 k = lim[x] - cnt[x] - 1;
        if (k < 0 || idx[x][k] < l) {
          ok = false;
        } else {
          v.push_back({idx[x][k], j});
        }
        cnt[x]++;
      }
      for (i64 j = t.size() - 1; j >= 0; j--) {
        i64 x = t[j] - '0';
        cnt[x]--;
      }
      if (!ok) continue;
      i64 sum = 0;
      sort(v.begin(), v.end());
      for (i64 j = 0; j < v.size(); j++) {
        sum += r - v[j].first - 1 - (v.size() - j - 1);
      }
      sort(v.begin(), v.end(), [&](p2 a, p2 b){return a.second < b.second;});
      if (v.size() >= 2 && v[0].first > v[1].first) sum++;
      if (v.size() >= 3 && v[1].first > v[2].first) sum++;
      if (v.size() >= 3 && v[0].first > v[2].first) sum++;
      ans = min(ans, sum);
    }
    cout << (ans == 1e18 ? -1 : ans) << "\n";
  }
}