#include<bits/stdc++.h>
#if __has_include(<atcoder/all>)
#endif
using namespace std;
#define eb emplace_back
#define LL(...) ll __VA_ARGS__;lin(__VA_ARGS__)
#define FO(n) for(ll IJK=n;IJK-->0;)
#define fo(i,...) for(auto[i,i##stop,i##step]=for_range<ll>(0,__VA_ARGS__);i<i##stop;i+=i##step)
#define of(i,...) for(auto[i,i##stop,i##step]=for_range<ll>(1,__VA_ARGS__);i>=i##stop;i+=i##step)
#define fe(a,e,...) for(auto&&__VA_OPT__([)e __VA_OPT__(,__VA_ARGS__]):a)
#define defpp template<ostream&o=cout>void pp(const auto&...a){[[maybe_unused]]const char*c="";((o<<c<<a,c=" "),...);o<<'\n';}void epp(const auto&...a){pp<cerr>(a...);}
#define entry defpp void main();void main2();}int main(){my::io();my::main();}namespace my{
namespace my{
void io(){cin.tie(nullptr)->sync_with_stdio(0);cout<<fixed<<setprecision(15);}
using ll=long long;
template<class T>constexpr auto for_range(T s,T b){T a=0;if(s)swap(a,b);return array{a-s,b,1-s*2};}
template<class T>constexpr auto for_range(T s,T a,T b,T c=1){return array{a-s,b,(1-s*2)*c};}
void lin(auto&...a){(cin>>...>>a);}
auto encode_integer(char c){return c-'0';}
constexpr ll size10(auto x){x|=1;ll r=0;while(x>0)x/=10,++r;return r;}
template<class T>constexpr ll maxsize10(){return size10(numeric_limits<T>::max());}
bool amin(auto&a,const auto&b){return b<a?a=b,1:0;}
auto max(auto...a){return max(initializer_list<common_type_t<decltype(a)...>>{a...});}
template<class A,class B=A>struct pair{
  A a;B b;
  pair()=default;
  pair(A aa,B bb):a(aa),b(bb){}
  auto operator<=>(const pair&)const=default;
};
template<bool is_negative=false>struct infinity{
  template<integral T>static constexpr T ones(size_t n){return n?ones<T>(n-1)*10+1:0;}
  template<integral T>constexpr operator T()const{static constexpr T v=ones<T>(maxsize10<T>())*(1-is_negative*2);return v;}
  template<class T>constexpr bool operator==(const T&x)const{return static_cast<T>(*this)==x;}
};
constexpr infinity oo;
template<class...A>using pack_back_t=tuple_element_t<sizeof...(A)-1,tuple<A...>>;
}
namespace my{
template<class V>concept vectorial=is_base_of_v<vector<typename remove_cvref_t<V>::value_type>,remove_cvref_t<V>>;
template<class V>constexpr int depth=0;
template<vectorial V>constexpr int depth<V> =depth<typename V::value_type>+1;
template<class T>struct core_t_helper{using type=T;};
template<vectorial V>struct core_t_helper<V>{using type=typename core_t_helper<typename V::value_type>::type;};
template<class T>using core_t=core_t_helper<T>::type;
template<class V>struct vec;
template<int D,class T>struct hvec_helper{using type=vec<typename hvec_helper<D-1,T>::type>;};
template<class T>struct hvec_helper<0,T>{using type=T;};
template<int D,class T>using hvec=hvec_helper<D,T>::type;
template<class V>struct vec:vector<V>{
  static constexpr int D=depth<vec<V>>;
  using C=core_t<V>;
  using vector<V>::vector;
  vec(const auto&...a)requires(sizeof...(a)>=3){resizes(a...);}
  void resizes(const auto&...a){if constexpr(sizeof...(a)==D){ }else*this=make(a...);}
  static auto make(ll n,const auto&...a){
    if constexpr(sizeof...(a)==1)return vec<C>(n,array{a...}[0]);
    else return vec<decltype(make(a...))>(n,make(a...));
  }
  ll size()const{return vector<V>::size();}
  auto&emplace_back(auto&&...a){vector<V>::emplace_back(std::forward<decltype(a)>(a)...);return*this;}
  auto fold(const auto&f)const{
    pair<C,bool>r{};
    fe(*this,e){
      if constexpr(!vectorial<V>){
        if(r.b)f(r.a,e);
        else r={e,1};
      }else { }

    }
    return r;
  }
  auto max()const{return fold([](auto&a,auto b){if(a<b)a=b;}).a;}
  auto min()const{return fold([](auto&a,auto b){if(b<a)a=b;}).a;}
  auto rev()const{vec v=*this;ranges::reverse(v);return v;}
  auto pre_groups(C M=-1)const{
    assert(min()>=0);
    if(M==-1)M=max();
    ll n=size();
    vec<vec<int>>res(n+1,M+1,-1);
    fo(i,1,n+1){
      fo(x,M+1)res[i][x]=res[i-1][x];
      res[i][(*this)[i-1]]=i-1;
    }
    return res;
  }
};
template<class...A>requires(sizeof...(A)>=2)vec(const A&...a)->vec<hvec<sizeof...(A)-2,pack_back_t<A...>>>;
auto sin(){string s;lin(s);return s;}
template<class T=ll>auto sinen_integer(){vec<T>r;fe(sin(),e)r.eb(encode_integer(e));return r;}
}
namespace my{
auto decimal(ll x,ll L=-1){if(L==-1)L=size10(x);vec<ll>r;while(x)r.eb(x%10),x/=10;r.resize(L);return r;}
}
namespace my{entry
void main(){
  LL(N,Q);
  auto s=sinen_integer();

  vec<vec<ll>>v;
  fo(i,1000)if(i%8==0)v.eb(decimal(i,3).rev());

  ll A=10;
  auto pre=s.pre_groups(A);

  FO(Q){
    LL(l,r);--l;

    if(r-l==1){
      pp(s[l]%8==0?0:-1);
      continue;
    }else if(r-l==2){
      if((s[l]*10+s[l+1])%8==0){
        pp(0);
        continue;
      }else if((s[l+1]*10+s[l])%8==0){
        pp(1);
        continue;
      }else{
        pp(-1);
        continue;
      }
    }

    ll res=oo;

    fe(v,tar){
      vec<ll>cnt(A);
      vec<ll>pos(3,-1);
      of(i,3){
        ll cu=pre[r][tar[i]];
        FO(cnt[tar[i]]){
          if(cu==-1)break;
          cu=pre[cu][tar[i]];
        }
        pos[i]=cu;
        cnt[tar[i]]++;
      }
      if(pos.min()<l)continue;

      ll tmp=0; // pos[i]をr-3+i (i=0,1,2)の位置に移動させるコスト.

      tmp+=max((r-1)-pos[2],0);
      if(pos[2]<pos[0])pos[0]--;
      if(pos[2]<pos[1])pos[1]--;

      tmp+=max((r-2)-pos[1],0);
      if(pos[1]<pos[0])pos[0]--;

      tmp+=max((r-3)-pos[0],0);

      amin(res,tmp);
    }

    pp(res==oo?-1:res);
  }

}}