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: Runtime Error)

#include "bits/stdc++.h"
using namespace std;
typedef long long ll;
#define pb push_back
#define mp make_pair
 
// random generator
// mt19937 rndm(time(0));
 
// ll gcd(ll a, ll b)
// {
//     while (b>0)
//     {
//         ll tmp = a;
//         a = b;
//         b = tmp%b;
//     }
//     return a;
// }
 
 
// long long gcd(long long a, long long b) {
//  return a? gcd(b % a, a) : b;
// }
 
 
const int M=1e9+7;
ll powmod(ll a,ll b, ll mod) {ll res=1;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res%mod;}/* a^b%mod */
const int N=2e5+10;



int main() {	
    #ifndef ONLINE_JUDGE
        freopen("input.txt", "r", stdin);
        freopen("output.txt", "w", stdout);
    #endif
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
	
	int n, k;
	cin>>n>>k;
	int kk=(n+1)/2;
	if(kk>=k)cout<<"ES\n";
	else cout<<"NO\n";
	return 0;
}