rc test series

Question

A graph is said to be 2 colorable if each vertex can be colored either red or blue and no two vertices of the same color are connected by an edge.If some graph is not 2 colorable then we can reduce it to become  2 colorable by removing some edges.we are given simple graph with 101 nodes and k is the minimum number of edges that we have to delete in order to make this graph 2 colorable

(ex ;- k=0 if graph is already 2 colorable)

the minimum value of k to reach the worst case is ______?