Epic Christmas Tree Generator (YoloSwag) [C++]

#include<iostream>
#include<cstdlib>
#include<time.h>
using namespace std;

int main()
{
    int NumberOfRows;
    int Spaces;
    int Random;
    bool Please = false;
    srand(time(NULL));
    while(Please == false)
    {
        cout << "Number of rows:" << endl << "> ";
        cin >> NumberOfRows;

        if(NumberOfRows >= 70) cout << "You can't have trees that big." << endl;
        else if (NumberOfRows <= 8) cout <<"You can't have trees that small." << endl;
        else Please = true;
        cout << endl;
    }

    for (int x = 0; x <= NumberOfRows; x++)
    {
        if (x % 2 == 1) Spaces = (NumberOfRows - x - 1)/2;
        else Spaces = (NumberOfRows - x)/2;

        for (int y = 0; y <= Spaces; y++) cout << " ";
        for (int z = 0; z <= x; z++)
        {
            Random = rand() % 7 + 1;
            if (Random != 3) cout << "*";
            else cout << "O";
        }
        cout << endl;
    }
    Spaces = (NumberOfRows - 4)/2;
    for (int k = 0; k <= Spaces; k++) cout << " ";
    cout<<"|  |" << endl;
    for (int k = 0; k <= Spaces; k++) cout << " ";
    cout<<"|  |" << endl; //What is a for loop?
    system("PAUSE");
    return 0;
}

/* Output:

Number of rows:
> 40

                     *
                    **
                    ***
                   ****
                   O***O
                  ******
                  ******O
                 ********
                 O******O*
                OO*****O*O
                ****O******
               O*****O*****
               *O*O*********
              *****O*OO*****
              ********O**O**O
             *O*O***O**O*O***
             ******O****O*O**O
            ******O***********
            O*****O************
           *O******************
           ************O********
          *******O**************
          **O*****O***O**********
         ************O*********O*
         ************O***********O
        ***O***O****O*************
        *O*****************OO******
       *************************O*O
       ***************OO***O***O*O**
      *******O***O****************O*
      O*O*O*O****O*******************
     ***OO***********O***************
     **O*******O*******O*******O****O*
    ******OOO*************************
    O****************O*****O***********
   ****O********O****OO********O*******
   *************O***********O********O**
  *******OOO***OO*O*******O*O***O*OO****
  *O*****O************OO***O*******O*****
 O********O*O**********************O*O***
 ***********O***********O*****************
                   |  |
                   |  |
Press any key to continue . . .

(It looks better than this in a terminal, I promise)