#include <stdio.h>

#include <algorithm>
#include <cmath>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>

using namespace std;

void __print(int x) { cerr << x; }
void __print(long x) { cerr << x; }
void __print(long long x) { cerr << x; }
void __print(unsigned x) { cerr << x; }
void __print(unsigned long x) { cerr << x; }
void __print(unsigned long long x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\'' << x << '\''; }
void __print(const char *x) { cerr << '\"' << x << '\"'; }
void __print(const string &x) { cerr << '\"' << x << '\"'; }
void __print(bool x) { cerr << (x ? "true" : "false"); }

template <typename T, typename V>
void __print(const pair<T, V> &x) {
    cerr << '{';
    __print(x.first);
    cerr << ',';
    __print(x.second);
    cerr << '}';
}
template <typename T>
void __print(const T &x) {
    int f = 0;
    cerr << '{';
    for (auto &i : x) cerr << (f++ ? "," : ""), __print(i);
    cerr << "}";
}
void _print() { cerr << "]\n"; }
template <typename T, typename... V>
void _print(T t, V... v) {
    __print(t);
    if (sizeof...(v)) cerr << ", ";
    _print(v...);
}
#ifdef LOCAL
#define debug(x...)               \
    cerr << "[" << #x << "] = ["; \
    _print(x)
#else
#define debug(x...)
#endif

#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end());
#define REP(i, n) for (int i = 0; i < (int)(n); i++)
#define FOR(i, a, b) for (int i = (a); i < (b); i++)

typedef long long ll;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    string Sd, T;
    cin >> Sd >> T;
    reverse(Sd.begin(), Sd.end());
    reverse(T.begin(), T.end());

    bool flag = false;  //既に条件が満たされている
    REP(j, Sd.length() - T.length() + 1) {
        if (Sd.substr(j, T.length()) == T) {
            flag = true;
        }
    }
    if (flag) {
        string result;
        debug("already satisfied");
        REP(i, Sd.length()) {
            if (Sd[i] != '?') {
                result += Sd[i];
            } else {
                result += 'a';
            }
        }
        reverse(result.begin(), result.end());
        cout << result << endl;
        return 0;
    } else {
        REP(j, Sd.length() - T.length() + 1) {
            int loss = 1;
            REP(i, T.length()) {
                if (Sd[j + i] == T[i] || Sd[j + i] == '?') {
                    loss--;
                } else {
                    loss += 100000;
                }
                debug(j, i, Sd, T, Sd[j + i], T[i], loss);
            }
            if (loss <= 0) {
                string result;
                debug("find", j);
                REP(i, Sd.length()) {
                    if (i == j) {
                        result += T;
                        i += T.size() - 1;
                    } else if (Sd[i] != '?') {
                        result += Sd[i];
                    } else {
                        result += 'a';
                    }
                }
                reverse(result.begin(), result.end());
                cout << result << endl;
                return 0;
            }
        }

        cout << "UNRESTORABLE" << endl;
        return 0;
    }
}


Measured memory_bytes: 256