#include<bits/stdc++.h>
using namespace std;
int i=1000,a,b,c,d;
int main(){
	while(i<=9999){
		a=i%10;
		b=i/10%10;
		c=i/100%10;
		d=i/1000;
		if(a==d&&b==c) cout<<i<<endl;
		i++;
	}
	return 0;
}
/**************************************************************
	Problem: 1447
	User: zhangziang
	Language: C++
	Result: Accepted
	Time:6 ms
	Memory:2072 kb
****************************************************************/