def question(i, j):
    print("?", i, j)
    return int(input())

def answer(n):
    print("!", n)

N, M, L = map(int, input().split())

left = 0
right = 10**9+1
while left+1 < right:
    mid = (left+right)//2
    if question(mid, 1) == mid:
        left = mid
    else:
        right = mid

B = right

answer(pow(N, M**L, B))