#include<bits/stdc++.h>//20
using namespace std;
#define maxn 10005
char s[maxn],ans[maxn],s_[maxn];
bool used[maxn];
int n,p;
int main(){
	memset(used,0,sizeof(used));
	scanf("%d",&n);
	scanf("%s",s);
	scanf("%d",&p);
	for(int i=0;i<n;i++)
		s_[i]=s[i];
	s_[n]='\0';
	sort(s_,s_+n,less<char>());
	ans[0]=s[p-1];
	for(int i=1,j=p-1;i<n;i++){//n^2
		ans[i]=s_[j];
		used[j]=1;
		for(int u=n-1;u>=0;u--){//找下一个
			if(used[u]) continue;
			if(s_[j]==s[u]){j=u;break;}
		}
	}
	ans[n]='\0';
	printf("%s",ans);
	return 0;
}

又及

倒序还是20