import std.stdio, std.conv, std.string;
import std.algorithm, std.array, std.container;
import std.numeric, std.math;
import core.bitop;

T RD(T = string)() { static string[] ss; while(!ss.length) ss = readln.chomp.split; string res = ss[0]; ss.popFront; return res.to!T; }
string RDR()() { return readln.chomp; }
void ERR(T)(in T x) { stderr.writeln(x); }

long mod = pow(10, 9) + 7;
long moda(long x, long y) { return (x + y) % mod; }
long mods(long x, long y) { return ((x + mod) - (y % mod)) % mod; }
long modm(long x, long y) { return (x * y) % mod; }

void main()
{
	auto S = RD!string;
	auto T = RD!string;

	ulong pos = ulong.max;
	foreach (i; 0..S.length-T.length+1)
	{
		bool ng = false;
		foreach (j, c; T)
		{
			if (S[i+j] != c && S[i+j] != '?')
			{
				ng = true;
				break;
			}
		}
		if (!ng)
		{
			pos = i;
		}
	}
	if (pos == ulong.max) writeln("UNRESTORABLE");
	else
	{
		auto ans = S.dup;
		foreach (i; 0..T.length)
		{
			ans[pos+i] = T[i];
		}
		ans = ans.replace("?", "a");
		writeln(ans);
	}
	
	stdout.flush();
}