you give integer n there undirected graph n node number 0 n 1 you give 2D integer array edge edgesi ai bi denote exist undirected edge connect node ai bireturn number pair different node unreachable Example 1input n 3 edge 010212output 0explanation there pair node unreachable therefore return 0example 2input n 7 edge 0205241654output 14explanation there 14 pair node unreachable other0103061213141523263435364656therefore return 14 Constraints1 n 1050 edgeslength 2 105edgesilength 20 ai bi nai biThere repeat edge