#include <cstdio>
#include <vector>
# include <iostream>
using namespace std;
vector <int> G[100005];
bool sel[100005];
int x,y,i,j,n,m,nr;
void dfs(int x)
{
sel[x]=1;
while(!G[x].empty())
{
  if(!sel[G[x].back()]) dfs(G[x].back());
  G[x].pop_back();
}
}
int main()
{
    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);
      G[x].push_back(y);
      G[y].push_back(x);
      sel[i]=0;
   }
   for(int i=1;i<=n;++i)
   {
       if(!sel[i])
       {
           sel[i]=1;
           dfs(i);
           nr++;
       }
   }
  printf("%d",nr);
    return 0;
}