#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

int count(string str)
{
    int n = str.length();
 
    vector< vector<int> > dp(n+1, vector<int>(n+1));
   
    for (int i=0; i<n; i++)
        dp[i][i] = 1;

    for (int leng =2; leng<=n; leng++)
    {
        for (int i=0; i<n; i++)
        {
            int k = leng+i-1;
            if (str[i] == str[k])
                dp[i][k] = dp[i][k-1] +dp[i+1][k] + 1;
            else
                dp[i][k] = dp[i][k-1] +dp[i+1][k] -dp[i+1][k-1];
        }
    }

    return dp[0][n-1];
}

int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    
    int n,q;
    cin>>n>>q;
    string s;
    cin>>s;
    
    while(q--){
        int a;
        cin>>a;
        if(a == 1){
            int i,j;
            cin>>i>>j;
            int t;
            cin>>t;
            t%= 26;
            for(int x = i; x<=j; x++){
                int add = t;
                bool cha = false;
                if( int(s[x]+t) > 122){
                    cha = true;
                    add = int(s[x]+t) - 123;
                }
                if(!cha){
                    char cur = s[x]+add;

                    s[x] = cur;
                }
                else{
                    s[x] = 'a'+add;
                }
            }
            
        }
        else{
            int i,j;
            cin>>i>>j;
            string str = s.substr(i,j-i+1);
            cout<<count(str)<<endl;
        }
       
    }
    return 0;
}