#include<iostream>
#include<math.h>
using namespace std;
int main()
{
int n=1,m;
float sum=1;
cin>>m;
while(n<=m)
{
sum=sum*n;
n++;
}
cout<<sum<<endl;
return 0;
}
#include<iostream>
#include<math.h>
using namespace std;
int main()
{
int n=1,m;
float sum=1;
cin>>m;
while(n<=m)
{
sum=sum*n;
n++;
}
cout<<sum<<endl;
return 0;
}