import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;
import java.util.InputMismatchException;

public class Main {

	public static void main(String[] args) {
		Task task = new Task();
		task.solve();
	}

	static class Task {
		static final long MOD = (long) 1e9 + 7;

		public void solve() {
			Scan sc = new Scan();
			char[] s = sc.scanString().toCharArray();
			char[] t = sc.scanString().toCharArray();
			int len_t = t.length;
			int len_s = s.length;
			char[] res = new char[len_s];
			Arrays.fill(res, ' ');
			boolean supergood = false;
			for (int i = len_s - 1; i >= len_t - 1; --i) {
				boolean good = true;
				for (int j = 0; j < len_t; ++j) {
					char cs = s[i - j];
					char ct = t[len_t - j - 1];
					if (cs != '?' && cs != ct) {
						good = false;
						break;
					}
				}
				if (good) {
					supergood = true;
					System.arraycopy(t, 0, res, i - len_t + 1, len_t);
					break;
				}
			}
			if (!supergood) {
				System.out.println("UNRESTORABLE");
			} else {
				for (int i = 0; i < len_s; ++i) {
					if (res[i] == ' ')
						res[i] = s[i] == '?' ? 'a' : s[i];
				}
				System.out.println(res);
			}
		}
	}

	static class Scan {
		private byte[] buf = new byte[1024];
		private int index;
		private InputStream in;
		private int total;

		public Scan() {
			in = System.in;
		}

		public int scan() {
			if (total < 0)
				throw new InputMismatchException();
			if (index >= total) {
				index = 0;
				try {
					total = in.read(buf);
				} catch (IOException e) {
					throw new RuntimeException(e);
				}
				if (total <= 0)
					return -1;
			}
			return buf[index++];
		}

		public long scanLong() {
			long integer = 0;
			int n = scan();
			while (isWhiteSpace(n))
				n = scan();
			int neg = 1;
			if (n == '-') {
				neg = -1;
				n = scan();
			}
			while (!isWhiteSpace(n)) {
				if (n >= '0' && n <= '9') {
					integer *= 10;
					integer += n - '0';
					n = scan();
				} else
					throw new InputMismatchException();
			}
			return neg * integer;
		}

		public double scanDouble() throws IOException {
			double doub = 0;
			int n = scan();
			while (isWhiteSpace(n))
				n = scan();
			int neg = 1;
			if (n == '-') {
				neg = -1;
				n = scan();
			}
			while (!isWhiteSpace(n) && n != '.') {
				if (n >= '0' && n <= '9') {
					doub *= 10;
					doub += n - '0';
					n = scan();
				} else
					throw new InputMismatchException();
			}
			if (n == '.') {
				n = scan();
				double temp = 1;
				while (!isWhiteSpace(n)) {
					if (n >= '0' && n <= '9') {
						temp /= 10;
						doub += (n - '0') * temp;
						n = scan();
					} else
						throw new InputMismatchException();
				}
			}
			return doub * neg;
		}

		public String scanString() {
			StringBuilder sb = new StringBuilder();
			int n = scan();
			while (isWhiteSpace(n))
				n = scan();
			while (!isWhiteSpace(n)) {
				sb.append((char) n);
				n = scan();
			}
			return sb.toString();
		}

		public char scanChar() {
			int n = scan();
			while (isWhiteSpace(n))
				n = scan();
			return (char) n;
		}

		private boolean isWhiteSpace(int n) {
			if (n == ' ' || n == '\n' || n == '\r' || n == '\t' || n == -1)
				return true;
			return false;
		}
	}
}


Measured memory_bytes: 21460