#include <stdio.h>

main(){
	int zero = 0;
	int currentNumber; 

	while(zero!=1){
		scanf("%d",&currentNumber);
		if(currentNumber!=0){
			factorial(currentNumber);
		}else{
			factorial(currentNumber);
			zero=1;
		}
	}

}

factorial(input){
	int i, result=1;

	for(i=1; i<=input; i++){
		result*=i;
	}
	printf("Enter a number: %d",input);
	printf("! = %d\n",result);

}