import java.util.Scanner;
public class FactorialTest {
public static void main(String args[]){
int n;
Scanner y=new Scanner(System.in);
n=y.nextInt( );
int num=1;
int i=1;
while(i<=n)
{
num*=i;
i++;
}
System.out.print(num);
}
}
import java.util.Scanner;
public class FactorialTest {
public static void main(String args[]){
int n;
Scanner y=new Scanner(System.in);
n=y.nextInt( );
int num=1;
int i=1;
while(i<=n)
{
num*=i;
i++;
}
System.out.print(num);
}
}