#include <stdio.h>
int n, m, viz[100005], cnt;typedef struct nod
{int x;nod *a;} *pNod;pNod v[100005];void add(pNod &dest, int val){pNod p;p = new nod;p -> x = val;p -> a = dest;dest = p;}void citire(){freopen("dfs.in","r",stdin);freopen("dfs.out","w",stdout);scanf("%d %d",&n,&m);int i, x, y;for (i = 1; i <= m; i++){scanf("%d %d",&x,&y);add(v[x], y);add(v[y], x);}}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;}