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: Accepted)

// khodaya khodet komak kon
#include <bits/stdc++.h>
#define pb push_back
#define ers erase
#define ins insert
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define debug(x)  cerr << #x << " = " << x << endl
#define kill(x) return cout << x, 0;
#define IOS ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#pragma GCC optimize ("Ofast")
using namespace std;

typedef long long ll;
typedef long double ld;
typedef string str;
typedef pair<ll, ll> pll;
typedef vector<ll> vl;
typedef vector<pll> vpl;

const ld Pi = 3.14159265359;
const ll MOD = 1000 * 1000 * 1000 + 7;
const ll N = 2e5 + 10;
const ll INF = 1e18;
const ll LOG = 20;
ll n ,k;



int main(){
	IOS;
	cin >> n >> k;
	if (k <= n / 2 + (n % 2)) kill("YES");
	kill("NO");
	
	
	
	
	
	
	
	return 0;
}






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*/