Problem:
Score : 100 points

Problem Statement

Determine if we can choose K different integers between 1 and N (inclusive) so that no two of them differ by 1.

Constraints

1\leq N,K\leq 100

N and K are integers.

Input

Input is given from Standard Input in the following format:

N K

Output

If we can choose K integers as above, print YES; otherwise, print NO.

Sample Input 1

3 2

Sample Output 1

YES

We can choose 1 and 3.

Sample Input 2

5 5

Sample Output 2

NO

Sample Input 3

31 10

Sample Output 3

YES

Sample Input 4

10 90

Sample Output 4

NO

Solution in C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <bits/stdc++.h> 
 
#define INF INT_MAX
#define MOD 1000000007
#define PI  acos(-1)
 
using ll  = long long;
using ull = unsigned long long;
using P = std::pair<int, int>;
 
int main(int argc, char *argv[])
{
    double N, K;
    std::cin >> N >> K;

    if (N / K >= 1.5) {
        std::cout << "YES" << std::endl;
    } else {
        std::cout << "NO"  << std::endl;
    }
    return 0;
}