Isha and Odd Cycle

Isha doesn't like odd numbers. Suhana gives her a graph that may contain odd cycle. Isha have a chance to remove any one edge such that resulting graph does not contain odd cycle. How many such edges exist ? Input First line contains N and M, number of nodes and number of edges. Each of next M line contains two integers x and y where there is an edge between x and y. Output Print number o