#include<algorithm>

#include<iostream>

#include<cstring>

#include<cstdio>

#include<cmath>

#define LL long long

#define M 100020

using namespace std;

namespace IO{

	const int BS=(1<<20); int Top=0;

	char Buffer[BS],OT[BS],*OS=OT,*HD,*TL,SS[20]; const char *fin=OT+BS-1;

	char Getchar(){if(HD==TL){TL=(HD=Buffer)+fread(Buffer,1,BS,stdin);} return (HD==TL)?EOF:*HD++;}

	void flush(){fwrite(OT,1,OS-OT,stdout);}

	void Putchar(char c){*OS++ =c;if(OS==fin)flush(),OS=OT;}

	void write(int x){

		if(!x){Putchar('0');return;} if(x<0) x=-x,Putchar('-');

		while(x) SS[++Top]=x%10,x/=10;

		while(Top) Putchar(SS[Top]+'0'),--Top;

	}

	int read(){

		int nm=0,fh=1; char cw=Getchar();

		for(;!isdigit(cw);cw=Getchar()) if(cw=='-') fh=-fh;

		for(;isdigit(cw);cw=Getchar()) nm=nm*10+(cw-'0');

		return nm*fh;

	}

}

using namespace IO;

int n,m,p[M],nxt[M]; char s[M]; bool G[M][26];

int main(){

	n=read(),s[1]='a',nxt[0]=-1,memset(G,true,sizeof(G));

	for(int i=1;i<=n;i++) p[i]=read(),nxt[i]=i-p[i]; Putchar('a');

	for(int i=2;i<=n;i++){

		for(int j=nxt[i-1]+1;j>=0;j=nxt[j-1]+1){

			if(!j){for(int k=0;k<26;k++) if(G[i][k]){s[i]=k+'a';break;}}

			else if(nxt[i]==j) s[i]=s[j];

			else{G[i][s[j]-'a']=false;continue;}break;

		} Putchar(s[i]);

	}Putchar('\n'),flush(); return 0;

}