#include <algorithm>
#include <boost/optional.hpp>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <functional>
#include <iomanip>
#include <iostream>
#include <limits>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <string>
#include <tuple>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

#define REP(i, n) for(int i = 0, i##_MACRO = (n); i < i##_MACRO; i++)
#define RANGE(i, a, b) for(int i = (a), i##_MACRO = (b); i < i##_MACRO; i++)
#define EACH(e, a) for(auto&& e : a)
#define ALL(a) std::begin(a), std::end(a)
#define RALL(a) std::rbegin(a), std::rend(a)
#define FILL(a, n) memset((a), n, sizeof(a))
#define FILLZ(a) FILL(a, 0)
#define INT(x) (static_cast<int>(x))
#define PRECISION(x) std::fixed << std::setprecision(x)

using namespace std;

using ll = long long;
using VI = std::vector<int>;
using VI2D = std::vector<vector<int>>;
using VLL = std::vector<long long>;
using VLL2D = std::vector<vector<long long>>;

constexpr int INF = 2e9;
constexpr double EPS = 1e-10;
constexpr double PI = acos(-1.0);

constexpr int dx[] = {-1, 0, 1, 0};
constexpr int dy[] = {0, -1, 0, 1};

template <typename T, std::size_t N>
struct make_vector_type {
	using type =
		typename std::vector<typename make_vector_type<T, (N - 1)>::type>;
};

template <typename T>
struct make_vector_type<T, 0> {
	using type = typename std::vector<T>;
};

template <typename T, size_t N>
auto make_vector_impl(const std::vector<std::size_t>& ls, T init_value) {
	if constexpr(N == 0) {
		return std::vector<T>(ls[N], init_value);
	} else {
		return typename make_vector_type<T, N>::type(
			ls[N], make_vector_impl<T, (N - 1)>(ls, init_value));
	}
}

template <typename T, std::size_t N>
auto make_vector(const std::size_t (&ls)[N], T init_value) {
	std::vector<std::size_t> dimensions(N);
	for(int i = 0; i < N; i++) {
		dimensions[N - i - 1] = ls[i];
	}
	return make_vector_impl<T, N - 1>(dimensions, init_value);
}

template <typename T>
std::vector<T> make_vector(std::size_t size, T init_value) {
	return std::vector<T>(size, init_value);
}

template <typename T>
constexpr int sign(T x) {
	return x < 0 ? -1 : x > 0 ? 1 : 0;
}

template <>
constexpr int sign(double x) {
	return x < -EPS ? -1 : x > EPS ? 1 : 0;
}

template <typename T, typename U>
constexpr void chmax(T& m, U x) {
	m = max<T>(m, x);
}

template <typename T, typename U>
constexpr bool chmin(T& m, U x) {
	if(m < x) {
		return false;
	}
	m = x;
	return true;
}

template <typename T>
constexpr T square(T x) {
	return x * x;
}

int compare_key_strings(const string& s, const string& t, int i) {
	int n = s.size();
	int m = t.size();

	string s_dash = s.substr(i, m);
	int different_chars_count = 0;
	REP(i, m) {
		different_chars_count +=
			(s_dash[i] == '?' || s_dash[i] == t[i] ? 0 : 1);
	}
	return different_chars_count;
}

int main() {
	string s;
	string t;
	cin >> s;
	cin >> t;

	int n = s.size();
	int m = t.size();
	int min_diff = INF;
	int min_index = 0;
	REP(i, n - m + 1) {
		if(chmin(min_diff, compare_key_strings(s, t, i))) {
			min_index = i;
		}
	}
	if(min_diff != 0) {
		cout << "UNRESTORABLE" << endl;
		return 0;
	}
	string result(n, '?');
	REP(i, n) {
		if(min_index <= i && i < min_index + m) {
			result[i] = t[i - min_index];
		} else if(s[i] == '?') {
			result[i] = 'a';
		} else {
			result[i] = s[i];
		}
	}

	cout << result << endl;
	return 0;
}


Measured memory_bytes: 3644