// poj3623#include<algorithm>#include<iostream>#include<cstdlib>#include<cstring>#include<cstdio>#include<cmath>#include<ctime>#define LL long long#define inf 1<<30#define Pi acos(-1.0)#define free(a) freopen(a".in","r",stdin),freopen(a".out","w",stdout);using namespace std;const int maxn=300010;int sa[maxn],height[maxn],rank[maxn],n;char s[maxn],ch[maxn/10][20],ans[maxn];namespace Suffix {	int wa[maxn],wb[maxn],ww[maxn];	bool cmp(int *r,int a,int b,int l) {		return r[a]==r[b] && r[a+l]==r[b+l];	}	void da(char *r,int *sa,int n,int m) {		int i,j,p,*x=wa,*y=wb;		for (i=0;i<=m;i++) ww[i]=0;		for (i=1;i<=n;i++) ww[x[i]=r[i]]++;		for (i=1;i<=m;i++) ww[i]+=ww[i-1];		for (i=n;i>=1;i--) sa[ww[x[i]]--]=i;		for (p=0,j=1;p<n;j*=2,m=p) {			for (p=0,i=n-j+1;i<=n;i++) y[++p]=i;			for (i=1;i<=n;i++) if (sa[i]>j) y[++p]=sa[i]-j;			for (i=0;i<=m;i++) ww[i]=0;			for (i=1;i<=n;i++) ww[x[y[i]]]++;			for (i=1;i<=m;i++) ww[i]+=ww[i-1];			for (i=n;i>=1;i--) sa[ww[x[y[i]]]--]=y[i];			for (swap(x,y),p=x[sa[1]]=1,i=2;i<=n;i++)				x[sa[i]]=cmp(y,sa[i-1],sa[i],j) ? p : ++p;		}	}	void calheight(char *r,int *sa,int n) {		for (int i=1;i<=n;i++) rank[sa[i]]=i;		for (int k=0,i=1;i<=n;i++) {			if (k) k--;			int j=sa[rank[i]-1];			while (r[i+k]==r[j+k]) k++;			height[rank[i]]=k;		}	}}int main() {	scanf("%d",&n);	char ch[10];	for (int i=1;i<=n;i++) {		scanf("%s",ch);s[i]=ch[0];	}	s[n+1]=‘#‘;	int len=n;	for (int i=1;i<=n;i++) s[n+i+1]=s[n-i+1];	n=n+n+1;	Suffix::da(s,sa,n,300);	Suffix::calheight(s,sa,n);	int tot=0,l=1,r=len;	while (tot<len) {		int x=rank[l],y=rank[len-r+1+len+1];		if (x<y) ans[++tot]=s[l++];		else ans[++tot]=s[r--];	}	for (int i=1;i<=tot;i++) {		printf("%c",ans[i]);		if (i%80==0) puts("");	}    return 0;}