A

#include <bits/stdc++.h>

using namespace std;

#define _test   int _TEST; cin>>_TEST; while(_TEST--)

int main()
{
    _test
    {
        int n, k;
        cin>>n>>k;

        string s;
        cin>>s;

        int rem = n - k;

        vector<int> cnt(26);
        for(auto e: s)
            cnt[e-'a']++;

        for(auto e: cnt)
        {
            if(e == 0)      continue;

            int x = min(rem, (e/2)*2);
            rem -= x;
            e -= x;

            if(rem%2 && e)
                rem--;
        }

        if(!rem)        cout<<"Yes\n";
        else            cout<<"No\n";
    }
}