#include <bits/stdc++.h>
int x1, x2, x3, y11, y2, y3, length;
int main() {
  scanf("%d %d %d %d %d %d", &x1, &y11, &x2, &y2, &x3, &y3);
  length = (int)(sqrt(x1 * y11 + x2 * y2 + x3 * y3) + 0.01);
  if (x1 * y11 + x2 * y2 + x3 * y3 != length * length) {
    printf("-1\n");
    return 0;
  }
  if (x1 < y11) {
    int temp = x1;
    x1 = y11;
    y11 = temp;
  }
  if (x2 < y2) {
    int temp = x2;
    x2 = y2;
    y2 = temp;
  }
  if (x3 < y3) {
    int temp = x3;
    x3 = y3;
    y3 = temp;
  }
  if (x1 == length && x2 == length && x3 == length) {
    printf("%d\n", length);
    for (int i = 0; i < y11; i++) {
      for (int j = 0; j < x1; j++) printf("A");
      printf("\n");
    }
    for (int i = 0; i < y2; i++) {
      for (int j = 0; j < x2; j++) printf("B");
      printf("\n");
    }
    for (int i = 0; i < y3; i++) {
      for (int j = 0; j < x3; j++) printf("C");
      printf("\n");
    }
  } else if (x1 == length) {
    printf("%d\n", length);
    if (x2 != length - y11) {
      int temp = x2;
      x2 = y2;
      y2 = temp;
    }
    if (x3 != length - y11) {
      int temp = x3;
      x3 = y3;
      y3 = temp;
    }
    for (int i = 0; i < y11; i++) {
      for (int j = 0; j < x1; j++) printf("A");
      printf("\n");
    }
    for (int i = 0; i < length - y11; i++) {
      for (int j = 0; j < y2; j++) printf("B");
      for (int j = 0; j < y3; j++) printf("C");
      printf("\n");
    }
  } else if (x2 == length) {
    printf("%d\n", length);
    if (x1 != length - y2) {
      int temp = x1;
      x1 = y11;
      y11 = temp;
    }
    if (x3 != length - y2) {
      int temp = x3;
      x3 = y3;
      y3 = temp;
    }
    for (int i = 0; i < y2; i++) {
      for (int j = 0; j < x2; j++) printf("B");
      printf("\n");
    }
    for (int i = 0; i < length - y2; i++) {
      for (int j = 0; j < y11; j++) printf("A");
      for (int j = 0; j < y3; j++) printf("C");
      printf("\n");
    }
  } else if (x3 == length) {
    printf("%d\n", length);
    if (x1 != length - y3) {
      int temp = x1;
      x1 = y11;
      y11 = temp;
    }
    if (x2 != length - y3) {
      int temp = x2;
      x2 = y2;
      y2 = temp;
    }
    for (int i = 0; i < y3; i++) {
      for (int j = 0; j < x3; j++) printf("C");
      printf("\n");
    }
    for (int i = 0; i < length - y3; i++) {
      for (int j = 0; j < y11; j++) printf("A");
      for (int j = 0; j < y2; j++) printf("B");
      printf("\n");
    }
  } else {
    printf("-1\n");
  }
  return 0;
}
