#include <bits/stdc++.h>
using namespace std;
#define REP(i,a,n) for(int i=(a); i<(int)(n); i++)
#define rep(i,n) REP(i,0,n)
#define FOR(it,c) for(__typeof((c).begin()) it=(c).begin(); it!=(c).end(); ++it)
#define ALLOF(c) (c).begin(), (c).end()
typedef long long ll;
typedef unsigned long long ull;

#define MOD 1000000000000LL

int main(){
  ll N;
  cin >> N;

  ll ret = 1;
  for(ll p=1; p<=N; p++){
    ret *= p;
    ret %= MOD;
    if(ret == 0) break;
  }

  if(N > 19){
    printf("%012lld\n", ret);
  }else{
    printf("%lld\n", ret);
  }
  
  return 0;
}