#include <iostream>
#include <fstream>

using namespace std;

int main()
{int P,i,n,N;
ifstream fin("fact.in");
ofstream fout("fact.out");
fin >>P;
n=P;
for(i=1;i<=n;i++)
{(N)=(N)*i;

}

fout <<N;
fin.close();
fout.close();
return 0;
}