text: #include <stdio.h>
   
  int main(void) {
    int n, k;
    scanf("%d%d", &n, &k);
    int r, g, b;
    r = ((n * 2) + k - 1)/k;
    g = ((n * 5) + k - 1)/k;
    b = ((n * 8) + k - 1)/k;
    int tot = r + g + b;
    printf("%d", tot);
    return 0;
  }