#include<cstdio>
#include<iostream>
#include<cstdlib>
#include<cstring>
using namespace std;
int main()
{
	bool Is_found=false;
	int ans;
	char s[100];
	char t[100];
	scanf("%s",s);
	scanf("%s",t);
	for(int i=0;s[i];i++)
	{
		if(s[i]==t[0]||s[i]=='?')
		{
			int j;
			for(j=1;t[j]&&s[i+j];j++)
			{
				if(s[i+j]==t[j]||s[i+j]=='?')continue;
				else break;
			}
			if(t[j]==0){Is_found=true;ans=i;}
		}
	}
	for(int i=0;t[i];i++)s[ans+i]=t[i];
	for(int i=0;s[i];i++)if(s[i]=='?')s[i]='a';
	if(!Is_found)printf("UNRESTORABLE\n");
	else printf("%s",s);
	return 0;
}
