using System;
using System.Collections.Generic;
using System.Collections;
using System.Collections.Specialized;
using System.Linq;
using System.Text;
using System.IO;
using System.Reflection;
using static System.Math;
using System.Numerics;
static class Program{
	const int mod=(int)1e9+7;
	static void Main(){
		Sc sc=new Sc();
		var n=sc.I;
		var t="X"+sc.S;
		int m=sc.I;
		St st=new St(n+1);
		for(int i = 1;i<=n;i++) {
			st.Ud(i,1<<(t[i]-97));
		}
		StringBuilder sb=new StringBuilder();
		for(int i = 0;i<m;i++) {
			var e=sc.Sa;
			if(e[0]=="1"){
				st.Ud(int.Parse(e[1]),1<<(e[2][0]-97));
			}
			else{
				sb.Append(bits(st.Get(int.Parse(e[1]),int.Parse(e[2])))+"\n");
			}
		}
		Console.Write(sb);
	}
	static int bits(long bits){
		bits=(bits&0x55555555)+(bits>>1&0x55555555);
		bits=(bits&0x33333333)+(bits>>2&0x33333333);
		bits=(bits&0x0f0f0f0f)+(bits>>4&0x0f0f0f0f);
		bits=(bits&0x00ff00ff)+(bits>>8&0x00ff00ff);
		return (int)((bits&0x0000ffff)+(bits>>16&0x0000ffff));
	}
}
public class St{
	private long[] dat;
	private int m=1,cnt=0;
	public St(int n){
		while(m<n){m<<=1;}
		cnt=m+n-1;
		dat=new long[cnt];
	}
	public void Ud(int q,long b){
		q+=m-1;
		dat[q]=b;
		while(true){
			q=(q-1)>>1;
			if((q<<1)+2<cnt){dat[q]=dat[(q<<1)+1]|dat[(q<<1)+2];}
			else{dat[q]=dat[(q<<1)+1];}
			if(q==0){break;}
		}
	}
	private long Fdg(int a,int b,int k,int l,int r){
		if(r<a||b<l){return 0;}
		if(a<=l&&r<=b){return dat[k];}
		else{return Fdg(a,b,k*2+1,l,(l+r)>>1)|Fdg(a,b,k*2+2,(l+r+1)>>1,r);}
	}
	public long Get(int a,int b){return Fdg(a,b,0,0,m-1);}
}
public class Sc{
	public int I{get{return int.Parse(Console.ReadLine());}}
	public long L{get{return long.Parse(Console.ReadLine());}}
	public double D{get{return double.Parse(Console.ReadLine());}}
	public string S{get{return Console.ReadLine();}}
	public int[] Ia{get{return Array.ConvertAll(Console.ReadLine().Split(),int.Parse);}}
	public long[] La{get{return Array.ConvertAll(Console.ReadLine().Split(),long.Parse);}}
	public double[] Da{get{return Array.ConvertAll(Console.ReadLine().Split(),double.Parse);}}
	public string[] Sa{get{return Console.ReadLine().Split();}}
	public object[] Oa{get{return Console.ReadLine().Split();}}
	public int[] Ia2{get{return Array.ConvertAll(("0 "+Console.ReadLine()+" 0").Split(),int.Parse);}}
	public int[] Ia3(int a){return Array.ConvertAll((a.ToString()+" "+Console.ReadLine()).Split(),int.Parse);}
	public int[] Ia3(bool a,int b,bool c,int d){return Array.ConvertAll(((a?b.ToString()+" ":"")+Console.ReadLine()+(c?" "+d.ToString():"")).Split(),int.Parse);}
	public long[] La2{get{return Array.ConvertAll(("0 "+Console.ReadLine()+" 0").Split(),long.Parse);}}
	public long[] La3(int a){return Array.ConvertAll((a.ToString()+" "+Console.ReadLine()).Split(),long.Parse);}
	public long[] La3(bool a,int b,bool c,int d){return Array.ConvertAll(((a?b.ToString()+" ":"")+Console.ReadLine()+(c?" "+d.ToString():"")).Split(),long.Parse);}
	public double[] Da2{get{return Array.ConvertAll(("0 "+Console.ReadLine()+" 0").Split(),double.Parse);}}
	public double[] Da3(int a){return Array.ConvertAll((a.ToString()+" "+Console.ReadLine()).Split(),double.Parse);}
	public double[] Da3(bool a,int b,bool c,int d){return Array.ConvertAll(((a?b.ToString()+" ":"")+Console.ReadLine()+(c?" "+d.ToString():"")).Split(),double.Parse);}
	public T[] Arr<T>(int n,Func<T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f();}return a;}
	public T[] Arr<T>(int n,Func<int,T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(i);}return a;}
	public T[] Arr<T>(int n,Func<string[],T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(Console.ReadLine().Split());}return a;}
	public T[] Arr<T>(int n,Func<int,string[],T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(i,Console.ReadLine().Split());}return a;}
}

Measured memory_bytes: 28124