#include<stdio.h>
#include<vector>
#define pb push_back
#define maxn 100005
using namespace std;

int n,m,nrc;
int v[maxn];
vector <int> l[maxn];

void read()
{
    int i;
    int x,y;
    scanf("%d%d",&n,&m);
    for(i=1;i<=m;i++)
    {
        scanf("%d%d",&x,&y);
        l[x].pb(y);
        l[y].pb(x);
    }
}

void dfs(int k)
{
    v[k]=1;
    for(unsigned int i=0;i<l[k].size();i++)
     if(v[l[k][i]]==0)
      dfs(l[k][i]);
}

void solve()
{
    int i;
    for(i=1;i<=n;i++)
     if(v[i]==0)
     {
         nrc++;
         dfs(i);
     }
}

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

    read();
    solve();
    printf("%d",nrc);

    fclose(stdin);
    fclose(stdout);
    return 0;
}