#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

ifstream in("dfs.in");
ofstream out("dfs.out");


vector<int> a[111111];
bool l[111111];
int c[111111];
int n,m,i,s,x,y,st,dr,k=0,j;

int main()
{
    in>>n>>m;
    for(i=1;i<=m;++i)
    {
        in>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    for(j=1;j<=n;++j)
    {
        if(l[j]==true)
        {
            continue;
        }
        ++k;
        c[1]=j;
        l[j]=true;
        st=dr=1;
        while(st<=dr)
        {
            for(i=0;i<a[c[st]].size();++i)
            {
                if(l[a[c[st]][i]]==false)
                {
                    c[++dr]=a[c[st]][i];
                    l[c[dr]]=true;
                }
            }
            st++;
        }
    }
    out<<k;
    return 0;
}