#include <stdio.h>
#include <vector>
#include <queue>
#define NMax 100002
using namespace std;
vector <int> G[NMax];
vector <int>::iterator it;
int n,m,s,nr=0;
bool vizitat[NMax];
void read()
{
    int x,y;
    freopen("dfs.in","r",stdin);
    scanf("%d%d",&n,&m);
    for(int i=1;i<=m;i++)
    {
        scanf("%d%d",&x,&y);
        G[x].push_back(y);
        G[y].push_back(x);
    }
    fclose(stdin);
}

void bfs(int s)
{
    int from;
    queue<int> Q;
    Q.push(s);
    vizitat[s]=1;
    while(!Q.empty())
    {
        from=Q.front();
        Q.pop();
        for(it=G[from].begin();it!=G[from].end();it++)
        {
            if(!vizitat[*it])
            {
                vizitat[*it]=1;
                Q.push(*it);
            }
        }
    }
}
int main()
{
    read();
    for(int i=1;i<=n;i++)
    {
        if(!vizitat[i]) {nr++; bfs(i);}
    }
    freopen("dfs.out","w",stdout);
    printf("%d",nr);
    fclose(stdout);
    return 0;
}