#include<cstdio>
#include<queue>
#include<vector>
#define NMAX 100005
using namespace std;
vector<int>adiacent[NMAX];
int viz[NMAX],nr;
void DFS(int i)
{
    viz[i]=1;
    for(int j=0; j<adiacent[i].size(); ++j)
        if(!viz[adiacent[i][j]])
                DFS(adiacent[i][j]);
    }
int main()
{
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);
    int n,m,x,y;
    scanf("%d%d",&n,&m);
    for(int i=1; i<=m; ++i)
    {
        scanf("%d%d",&x,&y);
        adiacent[x].push_back(y);
        adiacent[y].push_back(x);
    }
    for(int i=1; i<=n; ++i)
    {
        if(!viz[i])
        {
            ++nr;
        }
        DFS(i);
    }

printf("%d",nr);
}