import std.stdio, std.string, std.conv, std.array;

string mathed(char[] s, char[] t)
{
    for (int i = cast(int)(s.length-t.length); i >= 0; i--) {
	if (s[i] == t[0] || s[i] == '?') {
	    int ii = i;
	    bool flag = true;
	    for (int j = 0; j < t.length;) {
		if (!(s[i] == t[j] || s[i] == '?')) {
		    flag = false;
		    break;
		}
		i++;
		j++;
	    }

	    if (flag) {
		for (int j = 0; j < t.length; j++) {
		    s[ii+j] = t[j];
		}
		return cast(string)s.replace("?", "a");
	    }
	    else {
		i = ii;
	    }
	}
    }
    return "UNRESTORABLE";
}


void main()
{
    char[] s = readln.chomp.dup;
    char[] t = readln.chomp.dup;

    writeln(mathed(s, t));

}
