import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int q = in.nextInt();
        String s = in.next();
        for(int ae=0; ae<q; ae++){
            int a = in.nextInt();
            if(a==2){
            int b = in.nextInt();
            int c = in.nextInt();
                String ss = s.substring(b, c+1);
                int y = pal(ss);
                System.out.println(y);
            }
            else {
            int b = in.nextInt();
            int c = in.nextInt();
            int d = in.nextInt();
            for(int i=b; i<=c; i++){
                int x=0;
                d = d%26;
                s = s.substring(0,i)+(s.charAt(i)+d)+s.substring(i+1);
            }
            }
        }
        
    }
    
   static int pal(String str)
{
    int N = str.length();
 
    // create a 2D array to store the count of palindromic
    // subsequence
    int cps[][] = new int[N+1][N+1];
 
    // palindromic subsequence of length 1
    for (int i=0; i<N; i++)
        cps[i][i] = 1;
 
    // check subsequence of length L is palindrome or not
    for (int L=2; L<=N; L++)
    {
        for (int i=0; i<N && (L+i-1)<N; i++)
        {
            int k = L+i-1;
            if (str.charAt(i) == str.charAt(k))
                cps[i][k] = cps[i][k-1] +
                            cps[i+1][k] + 1;
            else
                cps[i][k] = cps[i][k-1] +
                            cps[i+1][k] -
                            cps[i+1][k-1];
        }
    }
 
    // return total palindromic subsequence
    return cps[0][N-1];
}
    
}