#include <bits/stdc++.h>
using namespace std;
 
int main() {
	// your code goes here
	int t;
	cin>>t;
	string s;
	while(t--){
		int n,k;
		int freq[26] = {0};
		cin>>n>>k>>s;
		for(int i=0;i<n;i++){
			freq[s[i]-'a']++;
		}
		int count = 0;
		for(int i=0;i<26;i++){
			if(freq[i]&1) count++;
		}
 
		if((n-k)&1){
			if(count > k){
				if(count == k+1) cout<<"YES\n";
				else cout<<"NO\n";
			}else{
				cout<<"YES\n";
			}
		}else{
			if(count > k) cout<<"NO\n";
			else cout<<"YES\n";
		}
	}
	return 0;
}

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MTQKMSAwCmEKMiAwCmFiCjIgMQpiYQozIDEKYWJiCjMgMgphYmMKNiAyCmJhY2FjZAo2IDIKZmFnYnphCjYgMgp6d2FhZmEKNyAyCnRhYWdhYWsKMTQgMwp0dHJyYWFra3R0b29ycgo1IDMKZGViZGIKNSA0CmVjYWRjCjUgMwpkZWJjYQo1IDMKYWJhYWMK

14
1 0
a
2 0
ab
2 1
ba
3 1
abb
3 2
abc
6 2
bacacd
6 2
fagbza
6 2
zwaafa
7 2
taagaak
14 3
ttrraakkttoorr
5 3
debdb
5 4
ecadc
5 3
debca
5 3
abaac