#include<bits/stdc++.h>
using namespace std;
int main(){
	int x,h,a,b,c,d;
	scanf("%d",&x);
	a=x%10;
	b=x/10%10;
	c=x/100%10;
	d=x/1000;
	h=b*1000+a*100+d*10+c;
	printf("%d",h);
	
} 

/**************************************************************
	Problem: 1616
	User: zhengzihao3
	Language: C++
	Result: Accepted
	Time:7 ms
	Memory:2076 kb
****************************************************************/