#include <stdio.h>
#include <string.h>
const int maxn = 3000;
int f[maxn];
int main()
{
int i,j,n;
scanf("%d",&n);
memset(f,0,sizeof(f));
f[0] = 1;
for(i = 2;i <= n;i++)
{
int c = 0;
for(j = 0;j < maxn;j++)
{
int s = f[j] * i + c;
f[j] = s % 10;
c = s / 10;
}
}
for(j = maxn - 1;j >= 0;j--) if(f[j]) break;
for(i = j;i >= 0;i--) printf("%d",f[i]);
printf("\n");
return 0;
}