package yukicoder;

import java.util.HashMap;
import java.util.Scanner;

public class Q469 {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int q = sc.nextInt();
		long p1 = 1_000_000 + 7;
		long m1 = 1_000_000 + 9;
		long[] pow = new long[n];
		pow[0] = 1;
		for (int i = 1; i < n; ++i) {
			pow[i] = pow[i - 1] * p1 % m1;
		}
		long[] accum = new long[n];
		accum[0] = pow[0];
		for (int i = 1; i < n; ++i) {
			accum[i] = accum[i - 1] + pow[i];
		}

		HashMap<Long, Integer> map = new HashMap<>();
		map.put(0L, 0);
		long h1 = 0;
		for (int query = 0; query < q; ++query) {
			String s = sc.next();
			if (s.equals("!")) {
				int l = sc.nextInt();
				int r = sc.nextInt();
				int k = sc.nextInt();
				h1 += (accum[r - 1] - (l > 0 ? accum[l - 1] : 0)) * k;
				while (h1 < 0)
					h1 += m1;
				if (!map.containsKey(h1)) {
					map.put(h1, query + 1);
				}
			} else {
				System.out.println(map.get(h1));
			}
		}
	}
}