#include <iostream>
#include <stdio.h>
using namespace std;
FILE *f,*g;
struct graph
{
    int node, next;
}v[400002];
int start[100002],been[100002];
int n,m,sol;
void read()
{
    int k=0,x,y;
    fscanf(f,"%d %d",&n,&m);
    for(int i=1; i<=m; i++)
    {
        fscanf(f,"%d %d",&x,&y);
        v[++k].node=y;
        v[k].next=start[x];
        start[x]=k;
        v[++k].node=x;
        v[k].next=start[y];
        start[y]=k;
    }
}
void dfs(int node)
{
    been[node]=1;
    for(int i=start[node]; i; i=v[i].next)
        if(!been[v[i].node])
            dfs(v[i].node);
}
void solve()
{
    for(int i=1; i<=n; i++)
        if(!been[i])
        {
            sol++;
            dfs(i);
        }
}
void write()
{
    fprintf(g,"%d",sol);
}
int main()
{
    f=fopen("dfs.in","r");
    g=fopen("dfs.out","w");
    read();
    solve();
    write();
    fclose(f);
    fclose(g);
    return 0;
}