/*#include <stdio.h>
int main()
{
int a,b,c;
scanf("%d %d %d",&a,&b,&c);
for(int j = 1; j <c; j++){
a += b;
}
printf("%d",a);
return 0;
}*/
/*#include <stdio.h>
int main()
{
int n, i, num=0;
scanf("%d", &n);
for (i=1; i<=n; i++)
{
if(n%i ==0)
num++;
}
if(num == 2)
printf("prime");
else
printf("not prime");
return 0;
}*/
/*#include <stdio.h>
int main()
{
int n, k, i;
scanf("%d %d", &n, &k);
int sum = n;
if( k>1)
{
for(i =1;i<k; i++)
{
sum = sum*n;
}
}
else if(k == 1)
sum =n;
else
sum =1;
printf("%d", sum);
return 0;
}*/
#include <stdio.h>
int main()
{
n, k, i,sum = 1;
scanf("%d", &n);
for(i = n; i>=1; i--)
{
sum =sum*i;
}
printf("%d", sum);
return 0;
}