#include<bits/stdc++.h>
using namespace std;
int a; 
int main(){
   for(char i='A';i<='Z';i++){
   	a=i;
   	int k=a,b=0;
   	while(k>0){
   		b*=10;
   		b+=k%10;
   		k/=10;
   	}
   	if(b==a){
   		cout<<i<<endl;
   	}
   }
   return 0;
}

/**************************************************************
	Problem: 1973
	User: chenjingqi
	Language: C++
	Result: Accepted
	Time:3 ms
	Memory:2072 kb
****************************************************************/