import random

N, Q = map(int, input().split())
MOD = (1 << 61) - 1
BASE = random.randrange(2, MOD)
cur = 0
d = {0: 0}
for i in range(1, Q + 1):
    query = input().split()
    if query[0] == '!':
        L, R, K = map(int, query[1:])
        cur += K * pow(BASE, L, MOD)
        cur -= K * pow(BASE, R, MOD)
        cur %= MOD
        if cur not in d:
            d[cur] = i
    else:
        print(d[cur])