while True:
    nilai = int(input('Masukkan nilai kocheng: '))
    if nilai <= 100:
        kelas = ''
        if nilai >= 86:
            kelas = 'A, beli!'
        elif nilai >= 76:
            kelas = 'B, beli!'
        elif nilai >= 66:
            kelas = 'C, beli!'
        elif nilai > 50:
            kelas = 'D, jangan beli!'
        else:
            kelas = 'E, jangan beli!'

        print(f'Kucing berkategori {kelas}')
        break