# Condensation of the graph

Find the number of edges in the condensation of a given directed graph.

The condensation of a directed graph $G$ is a directed graph $G_{′}$, whose vertices are strongly connected components of $G$, and the edge in $G_{′}$ is present only if there exists at least one edge between the vertices of corresponding connected components.

The graph condensation does not contain multiple edges.

## Input

The first line contains number of vertices $n$ and number of edges $m(n≤10_{4},m≤10_{5})$ in the graph. Each of the next $m$ lines describe the edge of the graph. The $i$-th edge is given with the starting $b_{i}$ and the ending $e_{i}(1≤b_{i},e_{i}≤n)$ vertex of the graph. The input graph can contain the multiple edges and loops.

## Output

Print the number of edges in graph condensation.