#include <bits/stdc++.h>
 #define ll long long
 #define ull unsigned long long
 #define pi 3.141592654
 #define NUM 1e18
 #define Mod  1'000'000'007
 #define fixed(n) fixed<<setprecision(n)
 #define cin(v) for(auto &i:v) cin >> i ;
 #define cout(v) for(auto &i:v) cout << i  <<" ";
 #define vowel(x) (x=='e'||x=='a'||x=='i'||x=='o'||x=='u')
 #define small(x) (x>=97&&x<=122)
 #define capital(x) (x>=65&&x<=90)
 #define Tolower(s) transform(s.begin(),s.end(),s.begin(),::tolower);
 #define Toupper(s) transform(s.begin(),s.end(),s.begin(),::toupper);
 #define all(v) ((v).begin()), ((v).end())
 #define allr(v) ((v).rbegin()), ((v).rend())
 #define updmax(a,b) a=max(a,b)
 #define updmin(a,b) a=min(a,b)
 //#define ceil(a,b) ((a/b)+(a%b?1:0))
 /* asc -> 1 2 3 ,des -> 3 2 1 */
 /***********************************************************************************/
 using namespace std;
 void Rofyda_Elghadban(){
  #ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout);
   #endif
    ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
 }

 void solve(){
  int n,k;
  cin>>n>>k;
  string s;
  cin>>s;
  map<char,int>mp;
  vector<int>o,e,v;
  for(int i=0;i<s.size();i++){
    mp[s[i]]++;
  }
  for(auto& i:mp){
    if(i.second%2!=0){
      o.push_back(i.second);
    }else{
      e.push_back(i.second);
    }
  }
  sort(all(o));
  sort(all(e));
  for(int i=0;i<o.size();i++){
    v.push_back(o[i]);
  }
  for(int i=0;i<e.size();i++){
    v.push_back(e[i]);
  }
  int l=0,countero=0,countere=0;
  for(int i=0;i<v.size();i++){
    if(k>=v[i]){
      l++;
      k-=v[i];
    }
  }
  for(int i=l;i<v.size();i++){
    if(v[i]%2!=0){
      countero++;
    }
  }
  if(countero>1){
    cout<<"NO"<<"\n";
  }else{
    cout<<"YES"<<"\n";
  }
 }


 int main(){
  Rofyda_Elghadban();
  int t;
  cin>>t;
  while(t--){
    solve();
  }
  // solve();
  return 0;
 }