#include <fstream>
#include <vector>
using namespace std;ifstream f("dfs.in");ofstream g("dfs.out");int n,m;vector<int>v[100001];int z[100001];void dfs(int x){z[x]=1;for(const int&y:v[x]){if(!z[y]){z[y]=1;dfs(y);}}}int main(){f>>n>>m;for(int x,y;m;--m){f>>x>>y;v[x].push_back(y);v[y].push_back(x);}int c=0;for(int i=1;i<=n;++i){if(z[i])continue;dfs(i);c++;}g<<c;return 0;}