#include <stdio.h>
#include <bitset>

using namespace std;
FILE *f,*g;
int start[100002],t[3][400004];
bitset <100002>viz;
int ss,m,n;

void dfs(int nod)
{
    int no;
    viz[nod]=1;
    no=start[nod];
    while(no)
    {
        if(!viz[t[0][no]])
            dfs(t[0][no]);
        no=t[1][no];
    }
}

void noduri()
{
    int i;
    for(i=1;i<=n;++i)
    {
        if(viz[i]==0)
        {
            ++ss;
            dfs(i);
        }
    }
}

int main()
{
    int i,j,o,k=0,nod,no;
    f=fopen("dfs.in","r");
    g=fopen("dfs.out","w");
    fscanf(f,"%d %d",&n,&m);
    for(o=1;o<=m;++o)
    {
        fscanf(f,"%d %d",&i,&j);
        ++k;
        t[0][k]=j;
        t[1][k]=start[i];
        start[i]=k;
        ++k;
        t[0][k]=i;
        t[1][k]=start[j];
        start[j]=k;
    }
    noduri();
    fprintf(g,"%d",ss);
    fclose(f);
    fclose(g);
    return 0;
}