#include <cstdio>
#include <vector>
#define pb push_back
using namespace std;
int NR, N, M, i, Sel[100001], x, y;
vector<int> G[100001];
inline void dfs(int x)
{
    vector<int> ::iterator it;
    Sel[x]=1;
    for (it=G[x].begin(); it!=G[x].end(); it++)
        if (!Sel[*it]) dfs(*it);
}
int main()
{
    freopen("dfs.in", "r", stdin);
    freopen("dfs.out", "w", stdout);
    scanf("%d%d", &N, &M);
    for (i=1; i<=M; i++)
    {
        scanf("%d%d", &x, &y);
        G[x].pb(y);
        G[y].pb(x);
    }
    for (i=1; i<=N; i++)
        if (!Sel[i])
        {
            dfs(i);
            NR++;
        }
    printf("%d\n", NR);
    return 0;
}