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
2850
2849
2848
2847
2846
2845
2844
2843
2842
2841
2840
2839
2838
2837
2836
2835
2834
2833
2832
2831
2830