using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;

class TEST{
	static void Main(){
		Sol mySol =new Sol();
		mySol.Solve();
	}
}

class Sol{
	public void Solve(){
		
		long mod = (long) 1e13+9;
		long[] ms = new long[N+1];
		var rnd = new Random();
		for(int i=0;i<N+1;i++){
			ms[i] = rnd.Next()%mod;
			if(ms[i] < 0) ms[i] += mod;
		}
		
		long[] res = new long[Q+1];
		long[] A = new long[N+1];
		long tot = 0;
		for(int i=0;i<N+1;i++) tot += A[i] * ms[i];
		res[0] = tot;
		Dictionary<long,int> his = new Dictionary<long,int>();
		his.Add(tot,0);
		List<int> L = new List<int>();
		for(int i=0;i<Q;i++){
			if(S[i][0] == '?'){
				res[i+1] = res[i];
				L.Add(his[res[i+1]]);
				continue;
			}
			
			var ss = S[i].Split();
			int a = int.Parse(ss[1]);
			int b = int.Parse(ss[2]);
			int k = int.Parse(ss[3]);
			
			tot += k * ms[a];
			tot -= k * ms[b];
			tot %= mod; if(tot<0) tot += mod;
			
			res[i+1] = tot;
			if(!his.ContainsKey(tot)){
				his.Add(tot,i+1);
			}
		}
		
		Console.WriteLine(String.Join("\n",L));
		
	}
	int N,Q;
	String[] S;
	public Sol(){
		var d = ria();
		N = d[0];
		Q = d[1];
		S = new String[Q];
		for(int i=0;i<Q;i++) S[i] = rs();
	}

	static String rs(){return Console.ReadLine();}
	static int ri(){return int.Parse(Console.ReadLine());}
	static long rl(){return long.Parse(Console.ReadLine());}
	static double rd(){return double.Parse(Console.ReadLine());}
	static String[] rsa(char sep=' '){return Console.ReadLine().Split(sep);}
	static int[] ria(char sep=' '){return Array.ConvertAll(Console.ReadLine().Split(sep),e=>int.Parse(e));}
	static long[] rla(char sep=' '){return Array.ConvertAll(Console.ReadLine().Split(sep),e=>long.Parse(e));}
	static double[] rda(char sep=' '){return Array.ConvertAll(Console.ReadLine().Split(sep),e=>double.Parse(e));}
}