#include <bits/stdc++.h>
using namespace std;
 
int main() {
 
	int n,k;
	cin>>n>>k;
 
	vector<int> numbers(n);
 
	for(auto& number: numbers){
		cin>>number;
	}
 
	unordered_map<int,int> lastIndex;
 
	bool answer = false;
 
	for(int i=0; i<n; i++){
		if(lastIndex.find(numbers[i]) != lastIndex.end()){
			if( i - lastIndex[numbers[i]] <= k ){
				answer = true;
				break;
			}
 
 
		}
 
		lastIndex[numbers[i]] = i;
 
	}
 
	(answer == true)?(cout<<"yes"):(cout<<"no");
 
	return 0;
}

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NSAyCjMgMiA0IDMgMQ==

5 2
3 2 4 3 1