#include <iostream>
#include <iomanip>
#include <vector>
#include <string>
#include <stack>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <algorithm>
#include <sstream>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <numeric>
#include <cmath>
#include <climits>
#include <limits>
#include <cfloat>
#include <fstream>
#include <list>
using namespace std;
 
int main()
{
   int n;
   cin>>n;
   long long result=1;
   for(int i=2;i<=n;i++){
     result*=i;
   }
   cout<<result<<endl;
   return 0;
}