#include<bits/stdc++.h>
using namespace std;
ifstream F("dfs.in");
ofstream G("dfs.out");
vector<int> v[100001];
int n,i,j,c;
bool a[100001];
void A(int i)
{
    a[i]=1;
    for(int j:v[i])
        if(!a[j])
            A(j);
}
int main()
{
    for(F>>n>>i;F>>i>>j;v[i].push_back(j),v[j].push_back(i));
    for(i=1;i<=n;!a[i]?++c,A(i):0,++i);
    return G<<c,0;
}