import sys
input = lambda :sys.stdin.readline()[:-1]
ni = lambda :int(input())
na = lambda :list(map(int,input().split()))
yes = lambda :print("yes");Yes = lambda :print("Yes");YES = lambda : print("YES")
no = lambda :print("no");No = lambda :print("No");NO = lambda : print("NO")
#######################################################################


"""

x >= B

x % B != x

"""
def euler_phi(n):
    res = n
    x = 2
    while x*x <= n:
        if n % x == 0:
            res = res // x * (x-1)
            while n % x == 0:
                n //= x
        x += 1
    if n > 1:
        res = res // n * (n-1)
    return res

def ask(x):
    print("?", x, 1, flush=True)
    return ni()

n, m, l = na()

ok = 10 ** 9 + 10
ng = 0

while ok - ng > 1:
    mid = ok + ng >> 1
    if ask(mid) != mid:
        ok = mid
    else:
        ng = mid

print("!", pow(n, pow(m, l), ok), flush=True)