def maximum (a,b,c):
    if(a>b) and (a>c):
        print(a,'is the largest number')
    elif(b>a and b>c):
        print(b,"is the largest number")
    else:
        print(c,'is the largest number')
maximum (25,13,20)
maximum (17,18,16)
maximum (39,38,40)