Forest

A forest is a graph without cycles, and each of its connected components is a tree. Given an undirected graph, is it a forest? In case it is, how many trees does it have?

Input

Input consists of several graphs. Every graph starts with its number of vertices $n$ and its number of edges $m$ , followed by $m$ pairs $x$ $y$ indicating an edge between vertices $x$ and $y$ . Assume $1 \le n \le 10^4$ , $0 \le m < n$ , that vertices are numbered from $0$ to $n-1$ , and that there are neither repeated edges nor edges of the type $x$ $x$ .

Output

For every graph, if it is a forest print the number of trees it has. Otherwise, print “no”.

Problem information

Author: Unknown
Translator: Albert Atserias

Generation: 2026-01-25T15:59:58.687Z