#include <bits/stdc++.h>
using namespace std;

int main(){
	int i,g,s,b,q;
	for(i = 1000;i <= 9999;i++){
		g = i % 10;
		s = i / 10 % 10;
		b = i / 100 % 10;
		q = i / 1000;
		
		if(q == g && s == b){
			cout<<i<<endl;
		}
	}
}


/**************************************************************
	Problem: 1447
	User: admin
	Language: C++
	Result: Accepted
	Time:10 ms
	Memory:2072 kb
****************************************************************/