import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.io.Closeable;
import java.io.IOException;
import java.util.NoSuchElementException;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author HBonsai
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        FastScanner in = new FastScanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        CDubiousDocument2 solver = new CDubiousDocument2();
        solver.solve(1, in, out);
        out.close();
    }

    static class CDubiousDocument2 {
        public void solve(int testNumber, FastScanner in, PrintWriter out) {
            String Sdash = in.next();
            String T = in.next();
            if (Sdash.length() < T.length()) {
                out.println("UNRESTORABLE");
                return;
            }
            for (int s = Sdash.length() - T.length(); s >= 0; s--) {
                boolean flag = true;
                for (int t = 0; t < T.length(); t++) {
                    if (Sdash.charAt(s + t) != T.charAt(t) && Sdash.charAt(s + t) != '?') {
                        flag = false;
                    }
                }
                if (flag) {
                    String S = Sdash.replace('?', 'a');
                    String ans0 = S.substring(0, s);
                    String ans1 = S.substring(s + T.length());
                    out.println(ans0 + T + ans1);
                    return;
                }
            }
            out.println("UNRESTORABLE");
        }

    }

    static class FastScanner implements Closeable {
        private final InputStream in;
        private final byte[] buffer = new byte[1024];
        private int ptr = 0;
        private int buflen = 0;

        public FastScanner(InputStream in) {
            this.in = in;
        }

        private boolean hasNextByte() {
            if (ptr < buflen) {
                return true;
            } else {
                ptr = 0;
                try {
                    buflen = in.read(buffer);
                } catch (IOException e) {
                    e.printStackTrace();
                }
                if (buflen <= 0) {
                    return false;
                }
            }
            return true;
        }

        private int readByte() {
            if (hasNextByte()) return buffer[ptr++];
            else return -1;
        }

        private static boolean isPrintableChar(int c) {
            return 33 <= c && c <= 126;
        }

        public boolean hasNext() {
            while (hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;
            return hasNextByte();
        }

        public String next() {
            if (!hasNext()) throw new NoSuchElementException();
            StringBuilder sb = new StringBuilder();
            int b = readByte();
            while (isPrintableChar(b)) {
                sb.appendCodePoint(b);
                b = readByte();
            }
            return sb.toString();
        }

        public void close() {
            try {
                in.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }
}



Measured memory_bytes: 22740