#include <cstdio>
#include <algorithm>
#include <list>

#define Nmax 100050

using namespace std;
list<int> G[Nmax];
int N,M;
int used[Nmax];

void read()
{
    scanf("%d%d",&N,&M);
    int a,b;
    for(int i = 1; i <= M; ++i){
        scanf("%d%d",&a,&b);
        G[a].push_back(b);
        G[b].push_back(a);
    }
}

void DFS(int k)
{
    used[ k ] = 1;
    for(list<int>::iterator it = G[k].begin(); it != G[k].end(); ++it)
        if(!used[ *it ])
            DFS(*it);
}

void solve()
{
    int cc = 0;
    for(int i = 1; i <= N; ++i)
        if(!used[i]){
            DFS(i);
            ++cc;
        }
    printf("%d\n",cc);
}

int main()
{
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);

    read();
    solve();

    return 0;
}