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

sum(10,20)

def sub(c,d):
    return c-d
sub(30,40)

def mul(e,f):
    return e*f
mul(5,50)



def isleap1(year):
    if year%4==0 :
        return True
    else:
        return False  
    
isleap1(2020)
        