A, B, C = map(int, input().split())
K = int(input())
mod = int(1e9) + 7
A = pow(A, pow(2, K, mod - 1), mod)
B = pow(B, pow(2, K, mod - 1), mod)
C = pow(C, pow(2, K, mod - 1), mod)
ans = (A * B * C) % mod
print(ans)