import java.util.Scanner; |
public class Main { |
public static void main(String[] args) { |
Scanner input = new Scanner(System.in); |
int N = input.nextInt(); |
long sum = 0 , num; |
int i, j; |
|
for (i = 1 ; i <= N; i++) |
{ |
num = 1 ; |
for (j = 1 ; j <= i; j++) |
{ |
num = num * j; |
} |
sum += num; |
} |
|
System.out.print(sum); |
|
input.close(); |
} |
} |