process.stdin.resume();
process.stdin.setEncoding('utf8');

var g_input = '';
process.stdin.on('data', function(chunk) {
    g_input += chunk;
});

process.stdin.on('end', function() {
    Main(g_input.split(/\r?\n/));
});

function Main(input) {

    var sdash = input[0];
    var t = input[1];

    var unrestorable = true;
    var matchPos = 0;
    for (var i = sdash.length - t.length; i >= 0; i--) {
        var isMatch = true;
        for (var j = 0; j < t.length; j++) {
            if (sdash.charAt(i + j) != '?' && sdash.charAt(i + j) != t.charAt(j)) {
                isMatch = false;
                break;
            }
        }
        if (isMatch) {
            unrestorable = false;
            matchPos = i;
            break;
        }
    }

    var s = '';
    if (unrestorable) {
        s = 'UNRESTORABLE';
    }
    else {
        for (var i = 0; i < sdash.length; i++) {
            if (i >= matchPos && i < matchPos + t.length) {
                s = s + t.charAt(i - matchPos);
            }
            else {
                if (sdash.charAt(i) == '?') {
                    s = s + 'a';
                }
                else {
                    s = s + sdash.charAt(i);
                }
            }
        }
    }

    console.log(s);

    return 0;
}
