#include<stdio.h>
#include<vector>

using namespace std;

#define Nmax 100010

int N,M,v[Nmax];
vector <int> l[Nmax];

void DF(int k)
{
    v[k]=1;

    for(int i=0;i<(int)l[k].size();++i)
        if (!v[ l[k][i] ])
            DF(l[k][i]);
}

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

void cit();

int main()
{
    cit();
    solve();
    return 0;
}

void cit()
{
    int a,b;
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);
    scanf("%d%d",&N,&M);
    for(int i=1;i<=M;++i)
        {
        scanf("%d%d",&a,&b);
        l[a].push_back(b);
        l[b].push_back(a);
        }
}