C :

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

C++ :

#include<bits/stdc++.h>
using namespace std;
int main()
{
	int n;
	cin>>n;
	int q = n / 1000;
	int b = n / 100 % 10;
	int s = n / 10 % 10;
	int g = n % 10;
	cout<<b*1000+q*100+g*10+s;
}

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 g = n % 10;
		int s = n / 10 % 10;
		int b = n / 100 % 10;
		int q = n / 1000;
		int sum = g * 10 + s + b * 1000 + q * 100;
		System.out.println(sum);
	}
}

Python :

a=int(input())
b=a//1000
c=a//100%10
d=a//10%10
e=a%10
print(c,b,e,d,sep='')