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
3900
3899
3898
3897
3896
3895
3894
3893
3892
3891
3890
3889
3888
3887
3886
3885
3884
3883
3882
3881
3880