def main():
    A,B,C = map(int,input().split()); MOD = pow(10,9) + 7
    K = int(input())
    x = pow(2,K,MOD-1)
    a = pow(A,x,MOD)
    b = pow(B,x,MOD)
    c = pow(C,x,MOD)
    ans = a*b*c%MOD
    print(ans)

if __name__ == '__main__':
    main()