#include <bits/stdc++.h>
using namespace std;
const int N = 100005;
int n, cnt, sum, len, tlen, tcnt;
int a[26], ans[N], tans[N], id[26], pos[N], tpos[N];
void work1() {
  printf("0\n");
  for (int i = 0; i < n; i++)
    for (int j = 1; j <= a[i]; j++) printf("%c", 'a' + i);
}
bool cmp(int x, int y) { return a[x] > a[y]; }
int gcd(int a, int b) { return b == 0 ? a : gcd(b, a % b); }
int t, d;
void work(int x, int y) {
  int j = 0;
  tcnt = tlen = 0;
  for (int i = x; i <= cnt; i += x) {
    while (j + 1 <= pos[i]) {
      j++;
      tans[++tlen] = ans[j];
    }
    if (i % (2 * x) == 0) {
      for (int l = 1; l <= y; l++) tans[++tlen] = t;
      tpos[++tcnt] = tlen;
      for (int l = 1; l <= y; l++) tans[++tlen] = t;
    } else
      tpos[++tcnt] = tlen;
  }
  while (j < len) tans[++tlen] = ans[++j];
  cnt = tcnt;
  for (int i = 1; i <= cnt; i++) pos[i] = tpos[i];
  len = tlen;
  for (int i = 1; i <= len; i++) ans[i] = tans[i];
}
void work2(int x, int y) {
  int j = 0;
  tlen = 0;
  for (int i = x; i <= cnt; i += x) {
    while (j + 1 <= pos[i]) {
      j++;
      tans[++tlen] = ans[j];
    }
    for (int l = 1; l <= y; l++) tans[++tlen] = t;
  }
  while (j < len) tans[++tlen] = ans[++j];
  len = tlen;
  for (int i = 1; i <= len; i++) ans[i] = tans[i];
}
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; i++)
    scanf("%d", &a[i]), cnt += a[i] & 1, sum += a[i], id[i] = i;
  if (cnt > 1) {
    work1();
    return 0;
  }
  sort(id, id + n);
  cnt = 0;
  for (int i = 0; i < n; i++) {
    t = id[i];
    if (a[t] & 1) continue;
    if (len == 0) {
      len = a[t];
      cnt = len;
      for (int i = 1; i <= len; i++) ans[i] = t, pos[i] = i;
      continue;
    }
    d = gcd(cnt, a[t]);
    work(cnt / d, a[t] / d);
  }
  for (int i = 0; i < n; i++)
    if (a[id[i]] & 1) {
      t = id[i];
      if (len == 0) {
        len = a[t];
        cnt = len;
        for (int i = 1; i <= len; i++) ans[i] = t, pos[i] = i;
        continue;
      }
      d = gcd(cnt, a[t]);
      work2(cnt / d, a[t] / d);
      cnt = d;
    }
  printf("%d\n", cnt);
  for (int i = 1; i <= len; i++) printf("%c", 'a' + ans[i]);
  return 0;
}
