#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n, q;
    string s;
    cin >> n >> q >> s;
    vector<tuple<int,int,int>> ls;
    vector<vector<int>> pos(10);
    for(int i = 0; i < n; i++) pos[s[i] - '0'].emplace_back(i);
    for(int i = 0; i < 1000; i += 8){
        ls.emplace_back(i / 100, i / 10 % 10, i % 10);
        auto [a, b, c] = ls.back();
    }
    auto get = [&](int d, int r){
        int p = lower_bound(pos[d].begin(), pos[d].end(), r) - pos[d].begin();
        p--;
        if(p == -1) return -1;
        return pos[d][p];
    };
    auto f = [&](int l, int r){
        // l以上 r 未満で最も大きいもの
        int ans = 1 << 30;
        if(r - l >= 2){
            for(auto [c2, c1, c0] : ls){
                if(r - l >= 3){
                    int p0 = get(c0, r);
                    if(p0 < l) continue;
                    int p1 = get(c1, r);
                    if(p1 == p0) p1 = get(c1, p1);
                    if(p1 < l) continue;
                    int p2 = get(c2, r);
                    if(p2 == p0) p2 = get(c2, p2);
                    if(p2 == p1) p2 = get(c2, p2);

                    if(p0 < p1) p1--;
                    if(p0 < p2) p2--;
                    if(p1 < p2) p2--;
                    int d = r - 1 - p0;
                    d += r - 2 - p1;
                    d += r - 3 - p2;
                    ans = min(ans, d);
                }else if(r - l == 2){
                    if(c2 != 0) break;
                    int p0 = get(c0, r);
                    if(p0 < l) continue;
                    int p1 = get(c1, r);
                    if(p1 == p0) p1 = get(c1, p1);
                    if(p1 < l) continue;
                    if(p0 < p1) p1--;
                    int d = r - 1 - p0;
                    d += r - 2 - p1;
                    ans = min(ans, d);
                }
            }
        }else{
            int v = s[l] - '0';
            if(v % 8 == 0) return 0;
        }
        if(ans >> 30) ans = -1;
        return ans;
    };
    while(q--){
        int l, r;
        cin >> l >> r;
        l--;
        cout << f(l, r) << '\n';
    }
}