#include<bits/stdc++.h>
using namespace std;
int main()
{
string m,n;
cin>>m>>n;
int i;bool fd=0;
for(i=0;i<=(int)(m.size()-n.size());i++)
{ int ans=0;
for(int j=0;j<(int)n.size();j++)
{
if(m[j+i]==n[j] || m[j+i]=='?')
{
ans++;
}
}
if(ans==(int)n.size()){
fd=1;
break;
}
}
if(fd){
string ap="";
for(int j=0;j<i;j++)
{ if(m[j]=='?')
m[j]='a';
ap+=m[j];
}
ap+=n;
cout<<ap<<endl;
}else{
cout<<"UNRESTORABLE\n";
}
return 0;
}
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