#include <stdio.h>
#include <vector>
#include <stack>

using namespace std;

FILE* f;
FILE* r;

int N, M, k;
vector<int> g[100003];
bool viz[100003];

void read()
{
    f = fopen("dfs.in", "r");

    fscanf(f, "%d%d", &N, &M);

    for (int i = 0; i < M; ++i)
    {
        int x, y;
        fscanf(f, "%d%d", &x, &y);        
        g[x].push_back(y);
        g[y].push_back(x);
    }
}

void dfs(int s)
{
    stack<int> q;
    q.push(s);
    viz[s] = true;

    while (!q.empty())
    {
        int x = q.top();
        q.pop();
        for (int i = 0; i < g[x].size(); ++i)
        {
            if (viz[g[x][i]] == false)
            {
                viz[g[x][i]] = true;
                q.push(g[x][i]);
            }
        }
    }
}

int main()
{
    r = fopen("dfs.out", "w");

    read();

    for (int i = 1; i <= N; i++)
        if (!viz[i])
        {
            dfs(i);
            k++;
        }

    fprintf(r, "%d", k);

    return 0;
}