#include <iostream>
#include <vector>
#include <fstream>
using namespace std;
ifstream in("dfs.in");
ofstream out("dfs.out");
bool viz[1005]={0};
bool A[1005][1005];
int N,M;
void citirematrice()
{int x,y;
    in>>N>>M;
    for(int i=1;i<=M;i++)
    {in>>x>>y;
   A[x][y]=A[y][x]=1;}
}
void afis()
{  cout<<"    ";
for(int i=1;i<=N;i++)
cout<<i<<" ";
cout<<endl;
    for(int i=1;i<=N;i++)
        {cout<<i<<" | ";
        for(int j=1;j<=N;j++)
        cout<<A[i][j]<<" ";
    cout<<endl;}
}
void DFS(int k)
{
    viz[k]=1;
    for(int i=1;i<=N;i++)
        if(!viz[i] && A[k][i])
        DFS(i);
}
int main()
{citirematrice();
int cnt=0;
for (int i = 1; i <= N; i++)
    if (!viz[i]) { cnt++; DFS(i);}
out<<cnt;

}