#include <cstdio>
#include <vector>
#include <stack>
#include <utility>
#define N 100001
using namespace std;

stack<pair<int,int> > st;
int viz[N];
vector<int> vec[N];

int main ()
{freopen("dfs.in","r",stdin);
 freopen("dfs.out","w",stdout);
 int i,n,m,x,y,p,flag,count;
 scanf("%d %d",&n,&m);
 for (i=1;i<=m;i++)
 {scanf("%d %d",&x,&y);
  vec[x].push_back(y);
  vec[y].push_back(x);
 }
 
 for (i=1,count=0;i<=n;i++)
 {if(viz[i]) continue;
  viz[i]=1;
  count++;
  st.push(make_pair(i,0));
  do
  {x=st.top().first;
   p=st.top().second;
   st.pop();
   for (;p<vec[x].size();p++)
   {if(viz[vec[x][p]])continue;
    viz[vec[x][p]]=1;
    st.push(make_pair(x,p+1));
    x=vec[x][p];p=-1;
   }
  }
  while(!st.empty());
 }

 printf("%d",count);
 return 0;
}