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

std::ifstream fin("dfs.in");
std::ofstream fout("dfs.out");

int n, m;
const int SIZE = 100005;

bool vizitat[SIZE];
std::vector<int> muchii[SIZE];

int insule = 0;

void DFS(int nod)
{
    vizitat[nod] = true;

    for(unsigned int i = 0; i < muchii[nod].size(); i++)
    {
        int vecin = muchii[nod][i];
        if(!vizitat[vecin])
            DFS(vecin);
    }
}

void citire()
{
    fin >> n >> m;

    int aux = n, x, y;

    while(--aux)
    {
        fin >> x >> y;

        muchii[x].push_back(y);
        muchii[y].push_back(x);
    }

    for(int i = 1; i <= n; ++i)
    {
        if(!vizitat[i])
        {
            insule++;
            DFS(i);
        }
    }
}

int main()
{
    citire();
    fout << insule;
    return 0;
}