#include <bits/stdc++.h>
using namespace std;
// #include <atcoder/modint>
// using namespace atcoder;
// using mint = modint998244353;
using ll = long long;
#define fix(x) fixed << setprecision(x)
#define rep(i, n) for(int i = 0; i < n; ++i)
#define all(x) (x).begin(),(x).end()
template<class T>bool chmin(T&a, const T&b){if(a>b){a=b;return 1;}return 0;}
template<class T>bool chmax(T&a, const T&b){if(a<b){a=b;return 1;}return 0;}
constexpr ll INFLL = (1LL << 62), MOD = 998244353;
constexpr int INF = (1 << 30);

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    vector<vector<int>> z;
    for(int i=112;i<1000;i+=8){
        vector<int> x(3);
        int y = i;
        bool f = true;
        rep(j,3){
            if(y%10==0) f = false;
            x[j] = y%10;
            y /= 10;
        }
        if(f) z.emplace_back(x);
    }
    int n,q;
    string s;
    cin >> n >> q >> s;
    vector<vector<int>> pre(n+1, vector<int>(10,-1));
    vector<int> y(10,-1);
    rep(i,n){
        y[s[i]-'0'] = i;
        rep(j,10) pre[i+1][j] = y[j];
    }
    while(q--){
        int l,r;
        cin >> l >> r;
        --l;
        if(r-l==1){
            cout << (s[l]=='8'?0:-1) << '\n';
            continue;
        }else if(r-l==2){
            int p = s[l]-'0', q = s[l+1]-'0', ans = -1;
            if(!((q*10+p)&7)) ans = 1;
            if(!((p*10+q)&7)) ans = 0;
            cout << ans << '\n';
            continue;
        }
        int ans = INF;
        for(auto& v:z){
            int upd = 0;
            vector<int> now(10,r), u(3);
            rep(i,3){
                int x = v[i], k = pre[now[x]][x];
                now[x] = k;
                u[i] = k;
                if(k<l){
                    upd = INF;
                    break;
                }
                upd += r-1-i-k;
            }
            if(u[2]>u[1]) swap(u[2],u[1]), ++upd;
            if(u[1]>u[0]) swap(u[1],u[0]), ++upd;
            if(u[2]>u[1]) swap(u[2],u[1]), ++upd;
            chmin(ans, upd);
        }
        if(ans==INF) ans = -1;
        cout << ans << '\n';
    }
    return 0;
}