#include<cstdio>
#include<queue>
#include<vector>

using namespace std;
const int nmax=100005;
vector <int> g[nmax];
queue<int>q;
bool viz[nmax];
int cc=0;
inline void bfs(int x)
{
    int top,pr;
    q.push(x);
    while(!q.empty())
    {
        top=q.front();
        q.pop();
        while(!g[top].empty())
        {
            pr=g[top].back();
            viz[pr]=1;
            g[top].pop_back();
        }
    }
}
int main()
{
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);
    int n,i,u,w,m;
    scanf("%d%d",&n,&m);
    for(i=1;i<=m;i++)
    {
        scanf("%d%d",&u,&w);
        g[u].push_back(w);
        g[w].push_back(u);
    }
    for(i=1;i<=n;i++)
    {
        if(!viz[i])
        {
            viz[i]=1;
            cc++;
            bfs(i);
        }
    }
    printf("%d",cc);
}