private void checkRange() {
		if (a == b)
			throw new RuntimeException("the first number{" + a + "} should not equals to second number{" + b + "}");
		if (a == c)
			throw new RuntimeException("the first number{" + a + "} should not equals to third number{" + c + "}");
		if (b == c)
			throw new RuntimeException("the second number{" + b + "} should not equals to third number{" + c + "}");
		if (0 >= a || a >= 10)
			throw new RuntimeException("the first number{" + a + "} should between 1 and 9");
		if (0 >= b || b >= 10)
			throw new RuntimeException("the second number{" + b + "} should between 1 and 9");
		if (0 >= c || c >= 10)
			throw new RuntimeException("the third number {" + c + "}should between 1 and 9");
	}