#include <bits/stdc++.h>   using namespace std;   int gcd(int x, int y) { return (y == 0 ? x : gcd(y, x % y)); }   const int N = (int)1e6 + 100;   int a[30];   int n;   int m = 0;   char s[N];   int main() {     scanf( %d , &n);     for (int i = 0; i < n; i++) scanf( %d , &a[i]);     for (int i = 0; i < n; i++) m += a[i];     if (n == 1) {       printf( %d n , m);       for (int i = 0; i < m; i++) s[i] =  a ;       s[m] = (char)0;       printf( %s n , s);       return 0;     }     int cntOdd = 0;     for (int i = 0; i < n; i++)       if (a[i] & 1) cntOdd++;     if (cntOdd > 1) {       printf( 0 n );       int idx = 0;       for (int i = 0; i < n; i++)         for (int j = 0; j < a[i]; j++) s[idx++] = (char)( a  + i);       s[m] = (char)0;       printf( %s n , s);       return 0;     }     if (cntOdd == 1) {       int g = 0;       for (int i = 0; i < n; i++) {         if (a[i] & 1)           g = gcd(g, a[i]);         else           g = gcd(g, a[i] / 2);       }       printf( %d n , g);       int idx = 0;       for (int i = 0; i < n; i++) {         if (a[i] & 1) continue;         for (int j = 0; j < a[i] / 2 / g; j++) s[idx++] = (char)( a  + i);       }       for (int i = 0; i < n; i++) {         if ((a[i] & 1) == 0) continue;         for (int j = 0; j < a[i] / g; j++) s[idx++] = (char)( a  + i);       }       for (int i = n - 1; i >= 0; i--) {         if (a[i] & 1) continue;         for (int j = 0; j < a[i] / 2 / g; j++) s[idx++] = (char)( a  + i);       }       int p = idx;       for (int i = p; i < m; i++) s[i] = s[i - p];       s[m] = (char)0;       printf( %s n , s);       return 0;     }     int g = 0;     for (int i = 0; i < n; i++) g = gcd(g, a[i] / 2);     printf( %d n , 2 * g);     int idx = 0;     for (int i = 0; i < n; i++)       for (int j = 0; j < a[i] / 2 / g; j++) s[idx++] = (char)( a  + i);     for (int i = n - 1; i >= 0; i--)       for (int j = 0; j < a[i] / 2 / g; j++) s[idx++] = (char)( a  + i);     int p = idx;     for (int i = p; i < m; i++) s[i] = s[i - p];     s[m] = (char)0;     printf( %s n , s);     return 0;   }   