Y \ X
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
4550
4549
4548
4547
4546
4545
4544
4543
4542
4541
4540
4539
4538
4537
4536
4535
4534
4533
4532
4531
4530