//階差数列のローリングハッシュをmapで持てば間に合う。
#include <iostream>
#include <map>
#define int long long
using namespace std;

int base = 467924537;
int mod = 1000000007;
int n, q;
char c; int l, r, val;
map<int, int> dict;

int powmod(int a, int n, int mod) {
	if (n == 0) return 1;
	if (n % 2 == 0) return powmod((a * a) % mod, n / 2, mod);
	return (a * powmod(a, n - 1, mod)) % mod;
}

signed main() {
	int i;
	
	cin >> n >> q;
	
	int hashNum = 0;
	for (i = 0; i < q; i++) {
		if (dict.find(hashNum) == dict.end()) dict[hashNum] = i;
		
		cin >> c;
		if (c == '!') {
			cin >> l >> r >> val;
			hashNum += val * powmod(base, l, mod);
			hashNum += (mod - val) * powmod(base, r, mod);
			hashNum %= mod;
		}
		else {
			cout << dict[hashNum] << endl;
		}
	}
	return 0;
}