C :

#include<stdio.h>
int main()
{
	int a,b;
	scanf("%d",&a);
	printf("%d",a-(a%10*1000+a/10%10*100+a/100%10*10+a/1000));
	return 0;
}

C++ :

#include<bits/stdc++.h>
using namespace std;
int main(){
	int i,a,b,c,d;
	cin>>i;
	a=i/1000;
	b=(i-a*1000)/100;
	c=(i-a*1000-b*100)/10;
	d=(i-a*1000-b*100-c*10)%10;
	cout<<i-d*1000-c*100-b*10-a<<endl;
}

Java :

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int x = sc.nextInt();
		int y =x%10*1000+x/10%10*100+x/100%10*10+x/1000%10;
		System.out.println(x-y);
	}

}

Python :

a=int(input())
b=a//1000
c=a//100%10*10
d=a//10%10*100
e=a%10*1000
f=e+d+c+b
print(a-f)