#include <cstdio>
#include <algorithm>
#include <vector>
#define Dim 100002

using namespace std;
int n, m, Sol;
bool viz[Dim];
vector <int> v[Dim];
void read()
{
    int x, y;
    freopen("dfs.in", "r", stdin);
    freopen("dfs.out", "w", stdout);
    scanf("%d %d", &n, &m);
    for(int i = 1; i <= m; ++ i)
    {
        scanf("%d %d", &x, &y);
        v[x].push_back(y);
        v[y].push_back(x);
    }
}
void DFS(int x)
{
    viz[x] = 1;
    for(int i = 0; i < v[x].size(); ++ i)
    {
        if(!viz[v[x][i]])
            DFS(viz[v[x][i]]);
        viz[v[x][i]] = 1;
    }
}
void solve()
{
    for(int i = 1; i <= n; ++ i)
        if(!viz[i])
        {
            DFS(i);
            Sol ++;
        }
}
void write()
{
    printf("%d\n", Sol);
}
int main()
{
    read();
    solve();
    write();
    return 0;
}