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
1510
1509
1508
1507
1506
1505
1504
1503
1502
1501
1500
1499
1498
1497
1496
1495
1494
1493
1492
1491
1490