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 <iostream>
#include <string>
#include <algorithm>
#include <cmath>
#include <map>
#include <vector>
#include <set>
#include <utility>
#include <cstdio>
using namespace std;
typedef long long LL;
#define rep(i, n) for (int i = 0; i < n; i++)
#define rrep(i, n, m) for (int i = n; i >= m; i--)

template <class T>
bool contain(const std::string &s, const T &v)
{
    return s.find(v) != std::string::npos;
}

int n,k;

int main()
{
    cin>>n>>k;
    if(n>k){
        cout << "YES" << endl;
    }else{
        cout<<"NO"<<endl;
    }
    
}