Image Credit: Wikimedia

def main():
    p1 = input("Enter 'rock', 'paper', or 'scissors' for player 1: ")
    p2 = input("Enter 'rock', 'paper', or 'scissors' for player 2: ")

    # determine the winner


main()

Player 1	Player 2	Output
rock	rock	tie
rock	paper	player 2 wins
rock	scissors	player 1 wins
paper	rock	player 1 wins
paper	paper	tie
paper	scissors	player 2 wins
scissors	rock	player 2 wins
scissors	paper	player 1 wins
scissors	scissors	tie

def main():
    p1 = input("Enter 'rock', 'paper', or 'scissors' for player 1: ")
    p2 = input("Enter 'rock', 'paper', or 'scissors' for player 2: ")

    if p1 == "rock" and p2 == "rock":
        print("tie")
    if p1 == "rock" and p2 == "paper":
        print("player 2 wins")
    if p1 == "rock" and p2 == "scissors":
        print("player 1 wins")
    if p1 == "paper" and p2 == "rock":
        print("player 1 wins")
    if p1 == "paper" and p2 == "paper":
        print("tie")
    if p1 == "paper" and p2 == "scissors":
        print("player 2 wins")
    if p1 == "scissors" and p2 == "rock":
        print("player 2 wins")
    if p1 == "scissors" and p2 == "paper":
        print("player 1 wins")
    if p1 == "scissors" and p2 == "scissors":
        print("tie")
    if (not (p1 == "rock" or p1 == "paper" or p1 == "scissors") and
                not (p2 == "rock" or p2 == "paper" or p2 == "scissors")):
        print("error")


main()

def main():
    p1 = input("Enter 'rock', 'paper', or 'scissors' for player 1: ")
    p2 = input("Enter 'rock', 'paper', or 'scissors' for player 2: ")

    if ((p1 == "rock" and p2 == "rock") or 
            (p1 == "paper" and p2 == "paper") or 
            (p1 == "scissors" and p2 == "scissors")):
        print("tie")
    if ((p1 == "rock" and p2 == "paper") or 
            (p1 == "paper" and p2 == "scissors") or 
            (p1 == "scissors" and p2 == "rock")):
        print("player 2 wins")
    if ((p1 == "rock" and p2 == "scissors") or 
            (p1 == "paper" and p2 == "rock") or 
            (p1 == "scissors" and p2 == "paper")):
        print("player 1 wins")
    if (not (p1 == "rock" or p1 == "paper" or p1 == "scissors") and 
            not (p2 == "rock" or p2 == "paper" or p2 == "scissors")):
        print("error")


main()