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
2660
2659
2658
2657
2656
2655
2654
2653
2652
2651
2650
2649
2648
2647
2646
2645
2644
2643
2642
2641
2640