public static boolean dif(int a, int b) {
		char[] numA = f(a).toCharArray();
		char[] numB = f(b).toCharArray();
		int mask = 0;
		for (int i = 0; i < numA.length; i++){
			if ((mask & (1 << (numA[i] - '0'))) == 0)
				mask |= (1 << (numA[i] - '0'));
			else
				return false;
			if ((mask & (1 << (numB[i] - '0'))) == 0)
				mask |= (1 << (numB[i] - '0'));
			else
				return false;
		}
		return true;
	}