#include<bits/stdc++.h>
using namespace std;
int main(){
    int a,b,c,d,e,n;
    cin>>n;
    a=n%10;
    b=n/10%10;
    c=n/100%10;
    d=n/1000;
    e=c*1000+d*100+a*10+b;
    cout<<e;
}
/**************************************************************
	Problem: 1219
	User: wengsihan
	Language: C++
	Result: Wrong Answer
****************************************************************/