C++ :

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
 
using namespace std;
 
string s1,s2,s3;
int Map[30]={0};
bool u[30]={0};
bool b[30]={0};
 
void init()
{
    cin>>s1>>s2>>s3;
    for(int i=0;i<s1.size();i++)
    {
        if(!u[s1[i]-'A'])
        {
            Map[s1[i]-'A']=s2[i]-'A';
            u[s1[i]-'A']=true;
            b[s2[i]-'A']=true;
        }
        else if(Map[s1[i]-'A']!=s2[i]-'A')
        {
            cout<<"Failed"<<endl;
            exit(0);
        }
    }
    for(int i='A'-'A';i<='Z'-'A';i++)
    {
        if(!u[i]||!b[i])
        {
            cout<<"Failed"<<endl;
            exit(0);
        }
    }
    for(int i=0;i<s3.size();i++)
    {
        cout<<(char)(Map[s3[i]-'A']+'A');
    }
}
 
int main()
{
    init();
     
    return 0;
}