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
4000
3999
3998
3997
3996
3995
3994
3993
3992
3991
3990
3989
3988
3987
3986
3985
3984
3983
3982
3981
3980