#define _CRT_SECURE_NO_WARNINGS
#include<sstream>
#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<climits>
#include<cmath>
#include<string>
#include<vector>
#include<set>
#include<map>
#include<queue>
#include<numeric>
#include<functional>
#include<algorithm>
#include<bitset>
#include<tuple>
#include<unordered_set>
#include<unordered_map>
#include<random>
using namespace std;
#define INF (1<<29)
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define all(v) v.begin(),v.end()
#define uniq(v) v.erase(unique(all(v)),v.end())



unsigned int xor128() {
	static unsigned int x = 123456789, y = 362436069, z = 521288629, w = 88675123;
	unsigned int t = (x ^ (x << 11));
	x = y; y = z; z = w;
	return w = (w ^ (w >> 19)) ^ (t ^ (t >> 8));
}


unsigned int rhash[1000001];

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);

	int n, q;
	scanf("%d%d", &n, &q);
	for (int i = 1; i <= n; i++) {
		rhash[i] = rhash[i - 1] + xor128();
	}
	unsigned int cur = 0;
	unordered_map<int, int> mp;
	mp[0] = 0;
	rep(i,q) {
		char c;
		scanf(" %c", &c);
		if (c == '?') {
			cout << mp[cur] << endl;
		}
		else {
			int l, r, k;
			scanf("%d%d%d", &l, &r, &k);
			cur += k * (rhash[r] - rhash[l]);
			auto it = mp.emplace(cur, i + 1);
		}
	}


	
	return 0;
}