#recursive function to find factorial n
def calcFactorial(n):
    print ("n=",n)
    if n == 0:
        factorial = 1
    else:
        factorial = n * calcFactorial(n-1)
    print("At A",factorial)                     #line A
    return factorial
#endsub

#main
x = calcFactorial(4)
print("At B",x)                                    #line B