import java.util.Scanner;
public class n的阶乘 {
public static void main(String[] args) {
Scanner sc =new Scanner(System.in);
int n = sc.nextInt();
int num[] = new int[10000000];
int i, j;
if (n == 1 || n == 0) {
System.out.println(1);
} else {
int p, h;// p 存放当前结果的位数,h为进位;
p = 1;
h = 0;
num[1] = 1;
for (i = 2; i <= n; i++) {
// 使得a[]的每位与i相乘
for (j = 1; j <= p; j++) {
num[j] = num[j] * i + h;
h = num[j] / 10;
num[j] = num[j] % 10;
}
// 表示向新的位置进位
while (h > 0) {
num[j] = h % 10;
h = h / 10;
j++;
}
p = j - 1;
}
for (i = p; i >= 1; i--) {
System.out.print(num[i]);
}
}
}
}