import java.util.Scanner;
public class A03求阶层之和 {
// 从控制台输入任意一个数字,求这个数的阶乘和. sum=1!+2!+3!+4...
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int a = sc.nextInt();
sc.close();
int sum = 0;
for (int i = 1; i <= a; i++) {
sum = sum + jieC(i); // 每次累加i的阶乘
}
System.out.println("通过计算,阶乘和为:" + sum);
}
// 设计一个函数,求n的阶乘
private static int jieC(int n) {
int sum = 1; // 初始值为1
for (int i = 1; i <= n; i++) {
sum = sum * i;
}
return sum;
}
}