#include <bits/stdc++.h>
using namespace std;
using ll=long long;
const ll ILL=2167167167167167167;
const int INF=2100000000;
#define rep(i,a,b) for (int i=(int)(a);i<(int)(b);i++)
#define all(p) p.begin(),p.end()
template<class T> using _pq = priority_queue<T, vector<T>, greater<T>>;
template<class T> int LB(vector<T> &v,T a){return lower_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> int UB(vector<T> &v,T a){return upper_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> bool chmin(T &a,T b){if(b<a){a=b;return 1;}else return 0;}
template<class T> bool chmax(T &a,T b){if(a<b){a=b;return 1;}else return 0;}
template<class T> void So(vector<T> &v) {sort(v.begin(),v.end());}
template<class T> void Sore(vector<T> &v) {sort(v.begin(),v.end(),[](T x,T y){return x>y;});}
bool yneos(bool a,bool upp=false){if(a){cout<<(upp?"YES\n":"Yes\n");}else{cout<<(upp?"NO\n":"No\n");}return a;}
template<class T> void vec_out(vector<T> &p,int ty=0){
    if(ty==2){cout<<'{';for(int i=0;i<(int)p.size();i++){if(i){cout<<",";}cout<<'"'<<p[i]<<'"';}cout<<"}\n";}
    else{if(ty==1){cout<<p.size()<<"\n";}for(int i=0;i<(int)(p.size());i++){if(i) cout<<" ";cout<<p[i];}cout<<"\n";}}
template<class T> T vec_min(vector<T> &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmin(ans,x);return ans;}
template<class T> T vec_max(vector<T> &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmax(ans,x);return ans;}
template<class T> T vec_sum(vector<T> &a){T ans=T(0);for(auto &x:a) ans+=x;return ans;}
int pop_count(long long a){int res=0;while(a){res+=(a&1),a>>=1;}return res;}
template<class T> T square(T a){return a * a;}



void solve();
// POP'N ROLL MUSIC / TOMOO
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int t = 1;
    // cin >> t;
    rep(i, 0, t) solve();
}

void solve(){
    int N, Q;
    cin >> N >> Q;
    string S;
    cin >> S;
    vector<vector<int>> p(10);
    rep(i, 0, N){
        p[S[i] - '0'].push_back(i);
    }
    vector<ll> cost(1000, INF);
    vector<vector<int>> order = {
            {0, 1, 2},
            {0, 2, 1},
            {1, 0, 2},
            {1, 2, 0},
            {2, 0, 1},
            {2, 1, 0}
    };
    vector<ll> inv = {0, 1, 1, 2, 2, 3};
    rep(i, 0, 1000){
        vector<int> v;
        {
            int tmp = i;
            rep(j, 0, 3) v.push_back(tmp % 10), tmp /= 10;
        }
        reverse(all(v));
        rep(j, 0, 6){
            int tmp = 0;
            rep(k, 0, 3) tmp *= 10, tmp += v[order[j][k]];
            if (tmp % 8 == 0) chmin(cost[i], inv[j]);
        }
    }
    while (Q--){
        int l, r;
        cin >> l >> r;
        l--;
        if (r - l == 1){
            cout << (S[l] == '8' ? 0 : -1) << "\n";
            continue;
        }
        if (r - l == 2){
            int tmp = stoi(S.substr(l, 2));
            if (tmp % 8 == 0){
                cout << "0\n";
            }
            else{
                tmp = (S[l + 1] - '0') * 10 + (S[l] - '0');
                cout << (tmp % 8 == 0 ? 1 : -1) << "\n";
            }
            continue;
        }
        vector<vector<ll>> q(10);
        rep(a, 1, 10){
            int b = LB(p[a], r);
            rep(k, 0, 3){
                b--;
                if (b >= 0 && p[a][b] >= l) q[a].push_back(p[a][b]);
                else q[a].push_back(-INF);
            }
            reverse(all(q[a]));
        }
        ll ans = ILL;
        vector<int> t = {1, 10, 100};
        auto f = [&](auto self, ll c, int ind, int val, ll ba = ILL) -> void {
            if (ind == 3){
                chmin(ans, c + cost[val]);
                return;
            }
            rep(a, 1, 10){
                ll b = q[a].back();
                if (b >= ba) continue;
                q[a].pop_back();
                self(self, c + (r - 1 - b - ind), ind + 1, val + t[ind] * a, b);
                q[a].push_back(b);
            }
        };
        f(f, 0, 0, 0);
        cout << (ans < INF ? ans : -1ll) << "\n";
    }
}

/*
 * 下 3 桁だけ
 * 125 通りしかないので全探索する？
 * 下から見て、どの位置にあるかを探すと
 * まあいけそう
 */