Insert Edges
addedge ( 0 , 2 ) ; addedge ( 1 , 2 ) ; addedge ( 2 , 3 ) ; addedge ( 3 , 4 ) ; addedge ( 4 , 6 ) ; addedge ( 4 , 5 ) ; addedge ( 5 , 7 ) ; addedge ( 5 , 8 ) ; cout << numberOfPairs ( N , Y , X ) ; return 0 ; }