#include <cstdio>
#include <vector>
#define DMAX 100001

using namespace std;
FILE * fin=fopen("dfs.in", "r");
FILE * fout=fopen("dfs.out", "w");

int n, m, nrc;
vector<int>L[DMAX];
bool viz[DMAX];

void citire();
void DFS(int vf);

int main()
{
int i;
citire();
for (i=1; i<=n; ++i)
    if (!viz[i])
    {
        nrc++;
        DFS(i);
    }
fprintf(fout, "%d\n", nrc);
return 0;
}

void DFS(int vf)
{
int i;
viz[vf]=1;
for (i=0; i<L[vf].size(); ++i)
    if (!viz[L[vf][i]])
        DFS(L[vf][i]);
}

void citire()
{
int i, x, y;
fscanf(fin, "%d %d", &n, &m);
for (i=1; i<=m; ++i)
    {
        fscanf(fin, "%d %d", &x, &y);
        L[x].push_back(y);
        L[y].push_back(x);
    }
}