#include<cstdio>
#include<vector>
#include<bitset>
using namespace std;
const int NMAX = 100005;
int n,m,i,x,y,nr;
vector<int> a[NMAX];
bitset<NMAX> B;
void dfs(int nod)
{
    for(vector<int>::iterator it=a[nod].begin();it!=a[nod].end();it++)
        if(!B[*it])
        {
            B[*it]=1;
            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);
        a[x].push_back(y);
        a[y].push_back(x);
    }
    for(i=1;i<=n;i++)
        if(!B[i]) {nr++; dfs(i);}
    printf("%d\n",nr);
    return 0;
}