#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
#define ud unsigned int
#define ll long long
#define ull unsigned long long
#define MAX_INF 0x3f
#define MAX_INF_VAL 0x3f3f3f3f
#define MAX_INF_VAL_LL 0x3f3f3f3f3f3f3f3f
//#define pi 3.141592653589
#define eps 1e-9
#define F(x) ((x)/3+((x)%3==1?0:tb))
#define G(x) ((x)<tb?(x)*3+1:((x)-tb)*3+2)
//#define p 2173412051LL
//#define sz 2

using namespace std;

template< typename T > void read( T &x ) {
	x = 0;
	char ch = getchar();
	ll f = 1;
	while( !isdigit( ch ) ) {
		if( ch == '-' )
		f *= -1;
		ch = getchar();
	}
	while( isdigit( ch ) ) {
		x = x * 10 + ch - 48;
		ch = getchar();
	}
	x *= f;
}

struct custom_hash {
    static uint64_t splitmix64( uint64_t x ) {
        x += 0x9e3779b97f4a7c15;
        x = ( x ^ ( x >> 30 ) ) * 0xbf58476d1ce4e5b9;
        x = ( x ^ ( x >> 27 ) ) * 0x94d049bb133111eb;
        return x ^ ( x >> 31 );
    }

    size_t operator() ( uint64_t x ) const {
        static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
        return splitmix64( x + FIXED_RANDOM );
    }
};

char s[ 100010 ];
int sum[ 100010 ];

int main() {
	ios::sync_with_stdio( false );
	cin.tie( 0 ), cout.tie( 0 );
	int n, m;
	int x, y;
	cin >> n >> m;
	cin >> s + 1;
	for( int i = 1; i <= n; ++i )
		sum[ i ] = sum[ i - 1 ] + s[ i ] - 'a' + 1;
	while( m-- ) {
		cin >> x >> y;
		cout << sum[ y ] - sum[ x - 1 ] << '\n';
	}
	return 0;
}