def tambah(a,b):
    return a+b

def kurang(a,b):
    return a-b

def bagi(a,b):
    return a/b

def kali(a,b):
    return a*b

def phi(r):
    if r > 7 and r % 7 == 0:
        return 22/7
    else:
        return 3.14
