#include <bits/stdc++.h>
#define NOD 100001
#define M 200001
using namespace std;
ifstream fin("dfs.in");ofstream fout("dfs.out");
vector<int> vecini[NOD];int n,m,x,y,contor=0;
bool used[NOD];
void dfs(int nod){for(auto it:vecini[nod])if(!used[it]){used[it]=true;dfs(it);}}
int main()
{
    fin>>n>>m;for(int copm=m;copm;copm--){fin>>x>>y;vecini[x].push_back(y);vecini[y].push_back(x);}
    for(int i=1;i<=n;++i)if(!used[i]){contor++;used[i]=true;dfs(i);}
    fout<<contor;
    return 0;
}