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
1640
1639
1638
1637
1636
1635
1634
1633
1632
1631
1630
1629
1628
1627
1626
1625
1624
1623
1622
1621
1620