/*
求 1!+ 2! + 3! + ...+ n! 的和
*/
#include <stdio.h>
int main() {
int n = 0;
scanf_s("%d",&n);
//求n个数的阶乘之和
int i = 1;
int j = 1;
int sum = 0;
for (j = 1; j <= n; j++) {
int res = 1;
//求某个数的阶乘
for (i = 1; i <= j; i++) {
res *= i;
}
sum += res;
}
printf("%d\n",sum);
return 0;
}