Language: Java

import static java.lang.System.out;

import java.io.IOException;
import java.io.InputStream;
import java.util.NoSuchElementException;

public class s100570405 {
    public static void main(String args[]) {
        new s100570405().run();
    }

    MyInput in = new MyInput();

    public void run() {
        String Sd = in.next();
        String T = in.next();
        int count = 0;
        char c;
        boolean ok = false;
        int first = -1;
        int end = -1;
        for (int j = 0; j < Sd.length(); j++) {
            count = 0;
            for (int i = 0; i + j < Sd.length(); i++) {
                c = Sd.charAt(i + j);
                if (c == '?' || c == T.charAt(count)) {
                    count++;
                    if (count == T.length()) {
                        first = i + j - T.length() + 1;
                        end = i + j;
                        ok = true;
                        break;
                    }
                } else count = 0;
            }
        }
        if (ok) {
            for (int i = 0; i < Sd.length(); i++) {
                if (first <= i && i <= end) {
                    out.print(T.charAt(i - first));
                } else {
                    if (Sd.charAt(i) == '?') out.print("a");
                    else out.print(Sd.charAt(i));
                }
            }
            out.println();
        } else {
            out.println("UNRESTORABLE");
        }
    }
}

class MyInput {
    private final InputStream in = System.in;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int buflen = 0;

    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;
    }

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

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

    private void skipUnprintable() {
        while (hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;
    }

    public boolean hasNext() {
        skipUnprintable();
        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 long nextLong() {
        if (!hasNext()) throw new NoSuchElementException();
        long n = 0;
        boolean minus = false;
        int b = readByte();
        if (b == '-') {
            minus = true;
            b = readByte();
        }
        if (b < '0' || '9' < b) {
            throw new NumberFormatException();
        }
        while (true) {
            if ('0' <= b && b <= '9') {
                n *= 10;
                n += b - '0';
            } else if (b == -1 || !isPrintableChar(b)) {
                return minus ? -n : n;
            } else {
                throw new NumberFormatException();
            }
            b = readByte();
        }
    }

    public int nextInt() {
        long nl = nextLong();
        if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
        return (int) nl;
    }

    public double nextDouble() {
        return Double.parseDouble(next());
    }
}


Example test case(s):
input: ?tc????
coder

output: atcoder