求1到给定数的阶乘的和

import java.util.Scanner;

public class Main1 {
public static void main(String args[]){
Scanner in = new Scanner(System.in);
while(in.hasNext()){
int a = in.nextInt();
int t=1,sum=0;
for(int i=1;i<=a;i++){
t=t*i;
sum=sum+t;
}
System.out.println(sum);
}
}

}