#include<bits/stdc++.h>
using namespace std;
string s1,s2,s3,s4;
int len,len2,a[30],v[30],t=0,num;
int main()
{
	//freopen("enc.in.txt","r",stdin);
	//freopen("enc.out.txt","w",stdout);
	memset(a,-1,sizeof(a));
	//memset(v,0,sizeof(v));
	cin>>s1>>s2>>s3;
	len=s1.length();
	len2=s3.length(); 
	//cout<<"len="<<len<<" len2="<<len2<<endl;
	for(int i=0;i<len;i++)
	{
	    //cout<<s2[i]-'a'<<"    "<<s1[i]-'a'<<endl;
		if(a[s2[i]-'a']==-1&&!v[s1[i]-'a'])
		{
			num++;	
		    a[s2[i]-'a']=s1[i]-'a';
		    v[s1[i]-'a']=1;
		}
		else if(a[s2[i]-'a']==s1[i]-'a')
		continue;
		else {
			cout<<"ERROR"<<endl;
			exit(0);
		}
	}
	if(num==25)
	{
		for(int i=0;i<=25;i++)
		{
			if(a[i]==-1)
			{
				for(int j=0;j<=25;j++)
				if(!v[j])
				{
				    a[i]=j;
				    break;
				}
				break;
			}
		}
	}
	for(int i=0;i<len2;i++)
	{
		//cout<<s3[i]-'a'<<endl;
		if(a[s3[i]-'a']!=-1)
		{
			s4[t++]=a[s3[i]-'a']+'a';
		}
		else {
			cout<<"ERROR"<<endl;
			return 0;
		}
	}
	for(int i=0;i<=t-1;i++)
	cout<<s4[i];
	cout<<endl;
	return 0;
}