#include <stdio.h>

int n, m, viz[100005], cnt;

typedef struct nod
{
    int x;
    nod *a;
} *pNod;
pNod v[100005];

void citire()
{
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);
    scanf("%d %d",&n,&m);
    int i, x, y;
    pNod p;

    for (i = 1; i <= m; i++)
    {
        scanf("%d %d",&x,&y);
        p = new nod;
        p -> x = x;
        p -> a = v[y];
        v[y] = p;
        p = new nod;
        p -> x = y;
        p -> a = v[x];
        v[x] = p;
    }
}

void DFS(int nod)
{
    pNod p;
    viz[nod] = 1;
    for (p = v[nod]; p != NULL; p = p -> a) if (!viz[p -> x]) DFS(p -> x);
}

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