#include <bits/stdc++.h>
using namespace std;
void swap(int *a, int *b) {
  int temp = *a;
  *a = *b;
  *b = temp;
}
void swap(char *a, char *b) {
  char temp = *a;
  *a = *b;
  *b = temp;
}
int main() {
  int xa, xb, xc, ya, yb, yc;
  cin >> xa >> ya >> xb >> yb >> xc >> yc;
  char ca = 'A', cb = 'B', cc = 'C';
  int area = xa * ya + xb * yb + xc * yc;
  int n = sqrt(area);
  if (n * n != area) {
    cout << -1;
    return 0;
  }
  char arr[n][n];
  if (xa < ya) swap(&xa, &ya);
  if (xb < yb) swap(&xb, &yb);
  if (xc < yc) swap(&xc, &yc);
  if (xb == n) {
    swap(&xa, &xb);
    swap(&ya, &yb);
    swap(&ca, &cb);
  } else if (xc == n) {
    swap(&xc, &xa);
    swap(&ya, &yc);
    swap(&ca, &cc);
  }
  if (xa != n) {
    cout << -1;
    return 0;
  }
  for (int i = 0; i < ya; i++) {
    for (int j = 0; j < n; j++) arr[i][j] = ca;
  }
  if (yb == yc && xb + xc == n && ya + yb == n) {
    for (int i = ya; i < n; i++) {
      for (int j = 0; j < n; j++) {
        if (j >= xb)
          arr[i][j] = cc;
        else
          arr[i][j] = cb;
      }
    }
  } else if (xb == xc && xb == n && ya + yb + yc == n) {
    for (int i = ya; i < n; i++) {
      for (int j = 0; j < n; j++) {
        if (i >= yb + ya)
          arr[i][j] = cc;
        else
          arr[i][j] = cb;
      }
    }
  } else if (xb == xc && yb + yc == n && ya + xb == n) {
    for (int i = ya; i < n; i++) {
      for (int j = 0; j < n; j++) {
        if (j >= yb)
          arr[i][j] = cc;
        else
          arr[i][j] = cb;
      }
    }
  } else if (xb == yc && yb + xc == n && ya + xb == n) {
    for (int i = ya; i < n; i++) {
      for (int j = 0; j < n; j++) {
        if (j >= yb)
          arr[i][j] = cc;
        else
          arr[i][j] = cb;
      }
    }
  } else if (yb == xc && xb + yc == n && ya + yb == n) {
    for (int i = ya; i < n; i++) {
      for (int j = 0; j < n; j++) {
        if (j >= xb)
          arr[i][j] = cc;
        else
          arr[i][j] = cb;
      }
    }
  } else {
    cout << -1;
    return 0;
  }
  cout << n << endl;
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) cout << arr[i][j];
    cout << endl;
  }
}
