/******************************************************************************
Online C++ Compiler.
Code, Compile, Run and Debug C++ program online.
Write your code in this editor and press "Run" button to compile and execute it.
*******************************************************************************/
#include <bits/stdc++.h>
using namespace std;
int main()
{
string s;
cin>>s;
for(int i=0;i<s.size();i++){
if(s[i]!=s[s.size()-i-1]&&s[i]!='?'&&s[s.size()-i-1]!='?')
{
cout<<"-1\n";
return 0;
}
if(s[i]==s[s.size()-1-i]&&s[i]=='?'){
s[i]=s[s.size()-1-i]='a';
continue;
}
if(s[i]=='?') s[i]=s[s.size()-i-1];
if(s[s.size()-i-1]=='?') s[s.size()-i-1]=s[i];
}
cout<<s<<"\n";
return 0;
}
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