/* THINK ALOUD !! */
#include <bits/stdc++.h>

using namespace std;
using ll=long long int;
using lld=long double;

#define mp make_pair
#define pb push_back
#define accu accumulate

#define vi vector<int>
#define vb vector<bool>
#define vc vector<char>
#define vd vector<double>
#define vlld vector<long double>
#define vll vector<long long int>

#define vvi vector<vector<int>>
#define vvb vector<vector<bool>>
#define vvc vector<vector<char>>
#define vvd vector<vector<double>>
#define vvlld vector<vector<long double>>
#define vvll vector<vector<long long int>>

#define pll pair<ll, ll>
#define pii pair<int, int>
#define pci pair<char, int>
#define pic pair<int, char>
#define pls pair<ll, string>
#define psl pair<string, ll>
#define pis pair<int, string>
#define psi paid<string, int>
#define fast std::ios_base::sync_with_stdio(0);std::cin.tie(0);std::cout.tie(0);

#define INF (int)1e9 // for INT_MAX which still allows for INF + INF
#define rep(i, a, n) for (ll i = a; i < n; i++)
#define per(i, a, n) for (ll i = n-1; i >= a; i--)
#define repp(i, a, n, p) for (ll i = a; i < n; i += p)
#define all(c) (c).begin(), (c).end()
#define lla(c) (c).rbegin(), (c).rend()
#define print_arr(arr, n) for (int i = 0; i < n; i++) std::cout << arr[i] << ' '; std::cout << '\n';
#define mod 1000000007
#define primeSize 2000000

void solve() {
    int n; cin >> n;
    int q; cin >> q;
    string s;
    cin >> s;

    vvi hash(n + 1, vi(27, 0));
    for (int i = 0; i < n; i++) {
        hash[i][s[i] - 'a'] ++;
        if (i != 0) {
            for (int j = 0; j < 27; j++) {
                hash[i][j] += hash[i - 1][j];
            }
        }
    }

    while (q --) {
        int l, r; cin >> l >> r;
        l --, r --;

        ll ans = 0;
        for (ll i = 0; i < 27; i++) {
            ll one = 0;
            if (l > 0) one = hash[r][i] - hash[l - 1][i];
            else one = hash[r][i];
            ans += (one) * (i + 1);
        }
        cout << ans << '\n';
    }

}

int main() {
    fast;
    int t = 1;
    while (t--)
        solve();
}
