#include <stdio.h>
int main(){
    int n;
    scanf("%d", &n);
    if(n < 0) {
        printf("Invalid input\n");
    }else{
        long long factorial = 1;
        for(int i =1; i <= n; i++){
            factorial *= i;
        }
        printf("%1111d\\n", factorial);
    }
    return 0;
}