#include <iostream>
#include <vector>
#include <math.h>
#include <cmath>
#include <algorithm>
#include <string>
#include <cstring>
#include <regex>
#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using pii = pair<int,int>;
using pl4 = pair<ll,ll>;
using vi = vector<int>;
using vvi = vector<vi>;
using vs = vector<string>;
using vvs = vector<vs>;
using vll = vector<ll>;
using vvll = vector<vll>;
using vpii = vector<pii>;
using vvpii = vector<vpii>;
using vpl4 = vector<pl4>;
using vvpl4 = vector<vpl4>;

#define fi first
#define se second
#define mp make_pair
#define pb push_back

#define FOR(i,a,b) for(int i=(a);i<=(b);i++)
#define rFOR(i,a,b) for(int i=(b);i>=(a);i--)
#define SORT(a) sort((a).begin(),(a).end())
#define rSORT(a) sort((a).rbegin(),(a).rend())
#define UNIQUE(a) (a).erase(unique((a).begin(),(a).end()),(a).end())
#define PREVP(a) prev_permutation((a).begin(),(a).end())
#define NEXTP(a) next_permutation((a).begin(),(a).end())
#define yn(a) cout <<((a)?"yes":"no")<<endl;
#define Yn(a) cout <<((a)?"Yes":"No")<<endl;
#define YN(a) cout <<((a)?"YES":"NO")<<endl;
#define Say(a) cout <<(a);
#define Sal(a) cout <<(a)<<endl;
#define dbg(a) cout <<(#a)<<": "<<(a)<<endl;
#define a2l(a) ((ll)(a-97))
#define A2l(a) ((ll)(a-65))
#define l2a(a) ((char)(a+97))
#define l2A(a) ((char)(a+65))
#define dNum2(a) ((llabs(a)==0)?(1):((ll)(log2(double(llabs(a))))+1))
#define dNum10(a) ((llabs(a)==0)?(1):((ll)(log10(double(llabs(a))))+1))

#define int ll

const ll MOD = 1e9+7;
const string alpha = "abcdefghijklmnopqrstuvwxyz";
const string ALPHA = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

ll gcd(ll a, ll b){if(b==0)return a;return gcd(b,a%b);}
ll lcm(ll a, ll b){return a/gcd(a,b)*b;}
ll min(ll a, ll b){if(a>=b) return b;if(a<b) return a;}
ll max(ll a, ll b){if(a>=b) return a;if(a<b) return b;}

ll dSum10(ll n){
    ll m=0;
    FOR(i,0,dNum10(n)-1){
        m+=(ll)((llabs(n)%(ll)(pow(10.0,(double)(i+1))))/(ll)(pow(10.0,(double)i)));
    }
    return m;
}

ll isP(ll n){
    if(n<=1) return 0;
    FOR(i,2,(ll)sqrt(n)){
        if(n%i==0) return 0;
    }
    return 1;
}

ll BinS(vll a,ll b){
    ll min=0,max=a.size()-1,mid=0;;
    while(1){
        mid=(min+max)/2;
        if(a[min]==b) return min;
        if(a[mid]==b) return mid;
        if(a[max]==b) return max;
        if(max-min<=2) return -1;
        if(a[mid]<b) min=mid;
        if(a[mid]>b) max=mid;
    }
}

//seiki
//#include <regex>
/*bubun*/
//regex_search("u32", regex("[0-9]"));      // true
/*kanzen*/
//regex_match("u32", regex("(i|u)\\d+"));   // true

signed main() {
    
    ll can=-1,chk=0;
    string S,T;
    cin >>S>>T;
    
    ll Ss=S.size(),Ts=T.size();
    
    rFOR(i,0,Ss-Ts){
        FOR(j,0,Ts-1){
            if((S[i+j]!='?')&&(S[i+j]!=T[j])){
                break;
            }else{
                if(j==Ts-1){
                    can=i;
                    chk=1;
                    break;
                }
            }
        }
        if(chk==1) break;
    }
    
    if(can==-1) Sal("UNRESTORABLE");
    if(can!=-1){
        FOR(i,0,Ss-1){
            if(S[i]=='?') S[i]='a';
            if((i>=can)&&(i<=can+Ts-1)) S[i]=T[i-can];
        }
        Sal(S);
    }
    
}

Measured memory_bytes: 256