C :

#include<stdio.h>

void main(){
	int n,i,j,t=1,s=0,f;
	scanf("%d",&n);
	
	f=1;
	for(i=1;i<=n;i++){
		t=t*i;
		s=s+t*f;
		f=f*-1;
		}
	printf("%d",s);
}

C++ :

#include <bits/stdc++.h>
using namespace std;
 
int main(){
    int n,i,j,f,s = 0,x;
    f = 1;
    cin>>n;
    for(i = 1;i <= n;i++){
    	x = 1;
    	for(j = 1;j <= i;j++){
    		x = x * j;
		}
    	s = s + f * x;
    	
    	f = f * -1;
	}
	
	cout<<s<<endl;
}

Java :

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int i,sum1=0,sum2=0;
		sc.close();
		for(i=1;i<=n;i++) {
			if(i%2==0) {
				sum1+=jiecheng(i);
			}else {
				sum2+=jiecheng(i);
			}	
		}
		System.out.println(sum2-sum1);
	}
	public static int jiecheng(int n) {
		int i,s=1;
		for(i=1;i<=n;i++) {
			s*=i;
		}return s;
	}
}

Python :

n = int(input())
s = 0
for i in range(1, n + 1):
    t = 1
    for j in range(1, i + 1):
        t = t * j
    if i % 2 == 1:
        s = s + t
    else:
        s = s - t
print(s)