#include <iostream>
#include <fstream>
using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");
int mx[100][100],v[100],i,j,x1,x2,n,m,k,co=0;
void dfs(int x)
{
    int i;
    v[x]=1;
    for (i = 1; i <= n; i++)
        if (!v[i] && mx[x][i])
            dfs(i);
}

int main()
{
    f>>n>>m;
    for(i=1; i<=m; i++)
    {
        f>>x1>>x2;
        mx[x1][x2]=mx[x2][x1]=1;
    }
    for(j=1; j<=n; j++)
        if(v[j]!=1)
        {
            dfs(j);
            co++;
        }
    cout << co;
    return 0;
}