#!/usr/bin/env python3

emeletek = int(input('Emelet? '))
emeletek_fele = int (emeletek / 2)

for emelet in range(emeletek):
    for _ in range(abs(emeletek_fele - emelet)):
        print(' ', end='')
    for _ in range((emeletek_fele - abs(emeletek_fele - emelet)) + 1):
        print('O', end='')
    print()