#include <bits/stdc++.h>
int main(void) {
  int H, W, i, n, m, x, y;
  for (i = 1; i <= 400; i++) {
    scanf("%d %d", &H, &W);
    if (H == 0 && W == 0) {
      i = 400;
    }
    for (n = 1; n <= H; n++) {
      y = n;
      for (x = 1; x <= 3000; x++) {
        y = y % 2;
      }
      if (y == 0) {
        for (m = 1; m <= W; m++) {
          y = m;
          for (x = 1; x <= 3000; x++) {
            y = y % 2;
          }
          if (y == 0) {
            printf("#");
          } else {
            printf(".");
          }
        }
        printf("\n");
      } else {
        for (m = 1; m <= W; m++) {
          y = m;
          for (x = 1; x <= 3000; x++) {
            y = y % 2;
          }
          if (y == 0) {
            printf(".");
          } else {
            printf("#");
          }
        }
        printf("\n");
      }
    }
    printf("\n");
  }
  return 0;
}
