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
3880
3879
3878
3877
3876
3875
3874
3873
3872
3871
3870
3869
3868
3867
3866
3865
3864
3863
3862
3861
3860