#include <bits/stdc++.h>
#include <numeric>
#define REP(i, s, n) for (int i = s; i < n; ++i)
#define rep(i, n) REP(i, 0, n)
#define SORT(c) sort((c).begin(), (c).end())
#define SORT_INV(c) sort((c).begin(), (c).end(), greater<int>())

#define IINF INT_MAX
#define LLINF LLONG_MAX
#define DEBUG false
#define LL long long
#define Dev 1000000007

// sort(a.begin(), a.end(), std::greater<int>());
using namespace std;

int main()
{
   int n;
   cin>>n;
   long long int ans = 1;
   for(int i=n;i>=1;i--){
       ans *= i;
   }
   cout << ans << endl;
   return 0;
}
