#include <cstdio>
#include <vector>

int vertices, edges, u, v, conexParts;

std :: vector<int> adj[100001]; bool visited[100001];

void DFS(int current)
{
    visited[current] = true;

    for(int child : adj[current])
    {
        if(!visited[child]) DFS(child);
    }
}

__attribute__((always_inline)) void read(int &num)
{
    static char inBuffer[0x2AB980];

    static unsigned int p = 0x2AB97F; num = 0x0;

    while(inBuffer[p] < 0x30 | inBuffer[p] > 0x39)
    {
        ++p != 0x2AB980 || (fread(inBuffer, 0x1, 0x2AB980, stdin), p = 0x0);
    }

    while(inBuffer[p] > 0x2F & inBuffer[p] < 0x3A)
    {
        num = num * 0xA + inBuffer[p] - 0x30;

        ++p != 0x2AB980 || (fread(inBuffer, 0x1, 0x2AB980, stdin), p = 0x0);
    }
}

int main()
{

    freopen("dfs.in", "r", stdin);
    freopen("dfs.out", "w", stdout);

    read(vertices); read(edges);

    for(int i = edges; i; --i)
    {
        read(u), read(v);

        adj[u].push_back(v);

        adj[v].push_back(u);
    }

    for(int i = vertices; i; --i)
    {
        if(!visited[i])
        {
            DFS(i);

            ++conexParts;
        }
    }

    printf("%d", conexParts);

    return 0;
}