#include <bits/stdc++.h>
#define INfile "dfs.in"
#define OUTfile "dfs.out"
#define LMax 100005

using namespace std;

ifstream fin(INfile);
ofstream fout(OUTfile);

int x,y,n, m, mat[LMax][LMax];
int v[LMax],nrcmp;

void dfs(int i)
{
    for (int j = 1; j <= n; ++j)
        if (mat[i][j] == 1 && v[j] == 0)
        {
            v[j] = 1;
            dfs(j);
        }
}
int main()
{
    fin >> n >> m;
    for(int i=1; i<=m; ++i)
    {
        fin>>x>>y;
        mat[x][y]=1;
        mat[y][x]=1;
    }
    for (int i = 1; i <= n; ++i)
    {
        if (v[i] == 0)
        {
            dfs(i);
            nrcmp++;
        }
    }
    fout<<nrcmp;
    return 0;
}