#include<bits/stdc++.h>
using namespace std;
const int maxn = 2005;
int n,l,r,cnt;
char cow[maxn];
bool check(int l,int r){
	while(l<r){
		if(cow[l]<cow[r]) return true;
		else if(cow[r]<cow[l]) return false;
		l++;r--;
	}
	return true;
}
int main(){
	freopen("blc.in","r",stdin);
	freopen("blc.out","w",stdout);
	scanf("%d",&n);
	for(int i=1;i<=n;i++)
	  scanf(" %c",&cow[i]);
	l=1;r=n;
	while(n--){
		if(cow[l]<cow[r]){
			putchar(cow[l]);
			l++;
		}
		else if(cow[r]<cow[l]){
			putchar(cow[r]);
			r--;
		}
		else if(check(l,r)){
			putchar(cow[l]);
			l++;
		}
		else{
			putchar(cow[r]);
			r--;
		}
		if(++cnt==80){
			putchar('\n');
			cnt=0;
		}
	}
	return 0;
}