Problem:
Score : 200 points

Problem Statement

There are some animals in a garden. Each of them is a crane with two legs or a turtle with four legs.

Takahashi says: "there are X animals in total in the garden, and they have Y legs in total." Determine whether there is a combination of numbers of cranes and turtles in which this statement is correct.

Constraints

1 \leq X \leq 100

1 \leq Y \leq 100

All values in input are integers.

Input

Input is given from Standard Input in the following format:

X Y

Output

If there is a combination of numbers of cranes and turtles in which the statement is correct, print Yes; otherwise, print No.

Sample Input 1

3 8

Sample Output 1

Yes

The statement "there are 3 animals in total in the garden, and they have 8 legs in total" is correct if there are two cranes and one turtle. Thus, there is a combination of numbers of cranes and turtles in which the statement is correct.

Sample Input 2

2 100

Sample Output 2

No

There is no combination of numbers of cranes and turtles in which this statement is correct.

Sample Input 3

1 2

Sample Output 3

Yes

We also consider the case in which there are only cranes or only turtles.

Solution in Java (OpenJDK 1.8.0) (judge verdict: Wrong Answer)


import java.util.*;

public class Main {
    static Scanner scanner;

    public static void main(String[] args) {
        scanner = new Scanner(System.in);
        int x = nextInt();
        int y = nextInt();
        double turu = 2 * x - y / 2.0;
        double kame = y / 2.0 - x ;
        if (Math.ceil(turu) == Math.floor(turu) && Math.ceil(kame) == Math.floor(kame)) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }

    public static void println(Object o) {
        System.out.println(o);
    }

    public static void print(Object o) {
        System.out.print(o);
    }

    public static void printf(String format, Object... o) {
        System.out.printf(format, o);
    }

    public static int nextInt() {
        return Integer.parseInt(scanner.next());
    }

    public static long nextLong() {
        return Long.parseLong(scanner.next());
    }

    public static double nextDouble() {
        return Double.parseDouble(scanner.next());
    }

    public static short nextShort() {
        return Short.parseShort(scanner.next());
    }

    public static float nextFloat() {
        return Float.parseFloat(scanner.next());
    }

    public static void printYes() {
        System.out.println("Yes");
    }

    public static void printYES() {
        System.out.println("YES");
    }

    public static void printNo() {
        System.out.println("No");
    }

    public static void printNO() {
        System.out.println("NO");
    }

    public static void nextLine() {
        scanner.nextLine();
    }

    public static double distance(double x, double y, double x2, double y2) {
        return Math.sqrt((x2 - x) * (x2 - x) + (y2 - y) * (y2 - y));
    }

    public static int MOD = 1_000_000_007;
    public static int MAX = 100000;
    public static long[] fac = new long[MAX];
    public static long[] finv = new long[MAX];
    public static long[] inv = new long[MAX];

    public static void combinit() {
        fac[0] = fac[1] = 1;
        finv[0] = finv[1] = 1;
        inv[1] = 1;
        for (int i = 2; i < MAX; i++) {
            fac[i] = fac[i - 1] * i % MOD;
            inv[i] = MOD - inv[MOD % i] * (MOD / i) % MOD;
            finv[i] = finv[i - 1] * inv[i] % MOD;
        }
    }

    public static long combination(int n, int k) {
        if (n < k || n < 0 || k < 0) return 0;
        return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
    }

    public static long factorial(long n) {
        return n <= 0 ? 1 : n * factorial(n - 1);
    }
}