import std;

void main() {
  char[] s, t;
  scan(s);
  scan(t);
  int n = s.length.to!int;
  int m = t.length.to!int;
  if (n < m) {
    writeln("UNRESTORABLE");
    return;
  }
  char[] ans = new char[](n);
  bool exist;
  foreach_reverse (i; 0 .. n - m + 1) {
    if (match(s[i .. i + m], t)) {
      foreach (j; 0 .. n) {
        if (i <= j && j < i + m) {
          ans[j] = t[j - i];
        } else {
          ans[j] = s[j];
        }
          
        if (ans[j] == '?') {
          ans[j] = 'a';
        }
      }
      exist = true;
      break;
    }
  }
  if (exist) {
    writeln(ans);
  } else {
    writeln("UNRESTORABLE");
  }
}

bool match(char[] s, char[] t) {
  foreach (i; 0 .. s.length) {
    if (s[i] == '?') {
      continue;
    }
    if (s[i] != t[i]) {
      return false;
    }
  }
  return true;
}

void scan(T...)(ref T args) {
    auto line = readln.split; // @suppress(dscanner.suspicious.unmodified)
    foreach (ref arg; args) {
        arg = line.front.to!(typeof(arg));
        line.popFront;
    }
    assert(line.empty);
}
 
void fillAll(R, T)(ref R arr, T value) {
    static if (is(typeof(arr[] = value))) {
        arr[] = value;
    }
    else {
        foreach (ref e; arr) {
            fillAll(e, value);
        }
    }
}
 
bool chmin(T, U...)(ref T x, U args) {
    bool isChanged;
    foreach (arg; args)
        if (x > arg) {
            x = arg;
            isChanged = true;
        }
    return isChanged;
}
 
bool chmax(T, U...)(ref T x, U args) {
    bool isChanged;
    foreach (arg; args)
        if (x < arg) {
            x = arg;
            isChanged = true;
        }
    return isChanged;
}
 
void yes(bool ok, string y = "Yes", string n = "No") {
    return writeln(ok ? y : n);
}