def Factorial1 (N):
    Counter = 1
    Result = 1
    while (Counter <= N):
        Result = Result * Counter
        Counter = Counter + 1
    return Result
    
def Factorial2 (N):
    Result = 1
    for Counter in range(1,N+1): Result *= Counter
    return Result
    
def Factorial3 (N):
    if (N <= 1): Result = 1
    else:        Result = N * Factorial3(N-1)
    return Result