#include <bits/stdc++.h>

using namespace std;

bitset <100055> f;

set <int> s[100055];

deque <int> q;

int main()
{
    ifstream cin("dfs.in");
    ofstream cout("dfs.out");
    int n,m,x,y;
    cin>>n>>m;
    for(int i=1;i<=m;++i)
    {
        cin>>x>>y;
        s[x].insert(y);
        s[y].insert(x);
    }
    int cnt=0;
    for(int i=1;i<=n;++i)
    {
        if(f[i]==0)
        {
            ++cnt;
            f[i]=1;
            q.push_back(i);
            while(q.size())
            {
                for(auto a:s[q.front()])
                {
                    if(f[a]==0)
                    {
                        f[a]=1;
                        q.push_back(a);
                    }
                }
                q.pop_front();
            }
        }
    }
    cout<<cnt;
    return 0;
}