n, m = map(int, input().split())
x = [0]*n
q = [0]*m
for i in range(m):
	q[i] = input().split()
	if q[i][0] == "!":
		for j in [1,2,3]:
			q[i][j] = int(q[i][j])
ans = {tuple(x[:]):0}
for i in range(m):
	if q[i][0] == "!":
		for j in range(q[i][2]-q[i][1]):
			x[q[i][1]+j] += q[i][3]
		if tuple(x) not in ans:
			ans[tuple(x[:])] = i+1
	else:
		print(ans[tuple(x)])