g = 20
G = g
izaberu = 0
while g > 1:
    if g % 3 == 0:
        g -= 2
    elif g % 2 == 0:
        g += 1
        izaberu -= 1
    else:
        izaberu += 1
        g -= 1
    if izaberu > G:
        izaberu,G = G,izaberu
    
print(f'イザベルの数:{izaberu}')