1 #include <iostream>
2 #include <cstdio>
3 #include <queue>
4 #include <cstring>
5 #include <string>
6 using namespace std;
7
8 int t,len,k,num,sum;
9 int a[27];
10 bool vis[27];
11 string str;
12 priority_queue<int, vector<int>,greater<int> > pq;
13
14 int main(){
15
16 scanf("%d",&t);
17 while(t--){
18 num=0;
19 sum=0;
20 memset(a,0,sizeof a);
21 memset(vis,0,sizeof vis);
22 while(!pq.empty())pq.pop();
23
24
25 scanf("%d",&k);
26 cin>>str;
27
28 len=str.length();
29 for(int i=0;i<len;i++){
30 a[ str[i]-'a']++;
31 vis[ str[i]-'a']=1;
32 }
33 for(int i=0;i<=25;i++){
34 if(vis[i]){
35 pq.push(a[i]);
36 num++;
37 }
38 }
39 if(num==1)
40 sum=pq.top(); //Pay attention to the situation ！
41 else{
42 for(int i=1;i<num;i++){
43 int t1=pq.top();pq.pop();
44 int t2=pq.top();pq.pop();
45 sum+=t1+t2;pq.push(t1+t2);
46 }
47
48 }
49
50 if(sum<=k)printf("yes\n");
51 else printf("no\n");
52 }
53 }
