#include <cstdio>
#include <vector>

#define NMAX 100001

using namespace std;

FILE *inFile = fopen("dfs.in", "r");
FILE *outFile = fopen("dfs.out", "w");

vector <int> G[NMAX];

int n;
bool viz[NMAX];

void read()
{
    int m;
    int x;
    int y;

    fscanf(inFile, "%d %d\n", &n, &m);

    while(m --)
    {
        fscanf (inFile, "%d %d\n", &x, &y);
        G[x].push_back(y);
        G[y].push_back(x);
    }
}

void dfs(int v)
{
    unsigned int m = G[v].size();
    for(unsigned int i = 0; i < m; ++ i)
    {
        int x = G[v][i];
        if(!viz[x])
        {
            viz[x] = 1;
            dfs(x);
        }
    }
}

int search()
{
    int k = 0;

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

    return k;
}

int main()
{
    read();
    fprintf(outFile, "%d\n", search());

    return 0;
}