Y \ X
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
1870
1869
1868
1867
1866
1865
1864
1863
1862
1861
1860
1859
1858
1857
1856
1855
1854
1853
1852
1851
1850