// codevs1170

#include<algorithm>

#include<iostream>

#include<cstdlib>

#include<cstring>

#include<cstdio>

#include<cmath>

#define LL long long

#define MOD 100000000

#define inf 2147483640

#define Pi acos(-1.0)

#define free(a) freopen(a".in","r",stdin),freopen(a".out","w",stdout);

using namespace std;

const int maxn=1010;

struct edge {int to,next;}e[maxn<<1];

int c[maxn],head[maxn],a[maxn],f[maxn],s1[maxn],s2[maxn];

int t1,t2,n,cnt;

void link(int u,int v) {

	e[++cnt].to=v;e[cnt].next=head[u];head[u]=cnt;

	e[++cnt].to=u;e[cnt].next=head[v];head[v]=cnt;

}

bool color(int x,int cl) {

	c[x]=cl;

	for (int i=head[x];i;i=e[i].next) {

		if (!c[e[i].to]) {if (!color(e[i].to,3-cl)) return 0;}

		else if (c[e[i].to]==cl) return 0;

	}

	return 1;

}

int main() {

	scanf("%d",&n);

	for (int i=1;i<=n;i++) scanf("%d",&a[i]);

	f[n+1]=inf;

	for (int i=n;i;i--) f[i]=min(f[i+1],a[i]);

	for (int i=1;i<=n;i++)

		for (int j=i+1;j<=n;j++)

			if (a[i]<a[j] && f[j+1]<a[i]) link(i,j);

	for (int i=1;i<=n;i++)

		if (!c[i] && !color(i,1)) {puts("0");return 0;}

	int now=1;

	for (int i=1;i<=n;i++) {

		if (c[i]==1) printf("a "),s1[++t1]=a[i];

		else printf("c "),s2[++t2]=a[i];

		while (s1[t1]==now || s2[t2]==now) {

			if (s1[t1]==now) printf("b "),t1--;

			else printf("d "),t2--;

			now++;

		}

	}

	return 0;

}