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

using namespace std;

const int Nmax=100005;

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

class Graf {
    int nrNoduri, nrMuchii;
    int Start;
    vector<vector<int>> vecini;
    int culoare[Nmax];          // pentru problema DFS

public:

    Graf(){
        nrNoduri = 0;
        nrMuchii = 0;
        Start = 0;
    };

    void BFS();
    void DFS(int nod, int color);
    void problema_DFS();
};

void Graf::DFS(int nod, int color)
{
    culoare[nod] = color;
    int l = vecini[nod].size();
    for(int i=0; i<l; i++)
    {
        int vec = vecini[nod][i];
        if(culoare[vec] == 0)
        {
            DFS(vec, color);
        }
    }
}

void Graf::problema_DFS()
{
    in>>nrNoduri>>nrMuchii;
    vecini.resize(nrNoduri+1);

    for(int i=0; i<nrMuchii; i++)
    {
        int x,y;
        in>>x>>y;
        vecini[x].push_back(y);
        vecini[y].push_back(x);
    }

    int nrCulori = 0;
    for(int nod=1; nod<=nrNoduri; nod++)
    {
        if(culoare[nod] == 0)
        {
            nrCulori++;
            DFS(nod, nrCulori);
        }
    }
    out << nrCulori;
}

void Graf::BFS()
{
    in>>nrNoduri>>nrMuchii>>Start;

    vector<int> vecini[nrNoduri+1];
    queue<int> coada;
    bool vizitat[nrNoduri+1];
    int inaltime[nrNoduri+1];

    for(int i=1; i<=nrNoduri+1; i++)
    {
        vizitat[i] = false;
        inaltime[i] = 0;
    }
    for(int i=0; i<nrMuchii; i++)
    {
        int x,y;
        in>>x>>y;
        vecini[x].push_back(y);
    }
    coada.push(Start);
    vizitat[Start] = true;
    while(!coada.empty())
    {
        int nod_curent = coada.front();
        coada.pop();
        int l = vecini[nod_curent].size();
        for(int i=0; i<l; i++)
        {
            int x = vecini[nod_curent][i];
            if(!vizitat[x])
            {
                vizitat[x] = true;
                coada.push(x);
                inaltime[x] = inaltime[nod_curent] + 1;
            }
        }
    }
    for(int i=1; i<=nrNoduri; i++)
    {
        if(inaltime[i] == 0 && i != Start)
            out << -1 <<' ';
        else
            out<<inaltime[i]<<' ';
    }
}

int main()
{
    Graf G;
    G.problema_DFS();
    in.close();
    out.close();
    return 0;
}