#include<bits/stdc++.h>
using namespace std;
typedef long long int lli;
typedef long double ld;
/*
#include <chrono> 
using namespace std::chrono;
#include <boost/multiprecision/cpp_int.hpp> 
using namespace boost::multiprecision;
#include <ext/pb_ds/assoc_container.hpp> 
#include <ext/pb_ds/tree_policy.hpp> 
using namespace __gnu_pbds; 
#define ordered_set tree<lli, null_type,less_equal<lli>, rb_tree_tag,tree_order_statistics_node_update> 
//remove _equal from less_equal to make it ordered set , currently it is ordered_multiset
*/
#define pb push_back
const lli mod=1e9+7;
const lli mod1=998244353;
#define fir first
#define sec second
#define plli pair<lli,lli>
#define pplli pair<lli,plli>
/*
lli power(lli a, lli b) {
    lli res = 1;
    while (b > 0) {
        if (b & 1)
            res = res * a;
        a = a * a;
        b >>= 1;
    }
    return res;
}
lli powermod(lli a, lli b) 
{
    lli res = 1;
    while (b > 0) {
        if (b & 1)
            res = ((res%mod)*(a%mod))%mod;
        a = (a * a)%mod;
        b >>= 1;
    }
    return res%mod;
}
*/
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    lli T,i,j;
    T=1;
    while(T--)
    {
        lli n,m;
        cin>>n>>m;
        string s;
        cin>>s;
        lli cnt[n+1][26];
        memset(cnt,0,sizeof(cnt));
        cnt[1][s[0]-'a']++;
        for(i=2;i<=n;i++)
        {
            for(j=0;j<26;j++)
            {
                cnt[i][j]=cnt[i-1][j];
            }
            cnt[i][s[i-1]-'a']++;
        }
        while(m--)
        {
            lli l,r;
            cin>>l>>r;
            lli cnt1[26]={0};
            for(i=0;i<26;i++)
            {
                cnt1[i]=cnt[r][i]-cnt[l-1][i];
            }   
            lli ans=0;
            for(i=0;i<26;i++)
            {
                ans+=((i+1)*cnt1[i]);
            }
            cout<<ans<<"\n";
        }
    }
    return 0;
}















