import std.stdio;
import std.string;
import std.conv;

void main() {
    string ans = "UNRESTORABLE";
    string s = readln.chomp;
    string t = readln.chomp;

    if (t.length <= s.length) {
        char[] t_ans;
        foreach_reverse (i; 0..s.length - t.length + 1) {
            bool flag = true;
            t_ans = s.dup;
            foreach_reverse (j; 0..t.length) {
                if (s[i + j] != t[j] && s[i + j] != '?'){
                    flag =  false;
                    break;
                } else {
                    t_ans[i + j] = t[j];
                }
            }
            if (flag) {
                ans = t_ans.to!string.tr("?", "a");
                break;
            }
        }
    }
    writeln(ans);
}