/*求阶乘问题，给出n(n＞0),求n！*/

/*求阶乘问题，给出n(n>0),求n！*/
#include<cstdio>
int factorial(int n);
int main(){
    int n;
    scanf("%d",&n);
    printf("%d",factorial(n));
    return 0;
}

int factorial(int n){
    int i,fact=1;
    for(i=1;i<=n;i++)
    fact=fact*i;
    return fact;
}