#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,a,b,c,d;
	cin>>n;
	a=n/1000;
	b=n/100%10;
	c=n/10%10;
	d=n%10;
	n=b*1000+a*100+d*10+c;
	cout<<n; 
}
/**************************************************************
	Problem: 1619
	User: panyuchen
	Language: C++
	Result: Accepted
	Time:7 ms
	Memory:2072 kb
****************************************************************/