#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define VMAX 100010
#define EMAX 1000010

int start[EMAX],target[EMAX],prev[EMAX],last[VMAX];
char viz[VMAX];
int edgeNo,nodeNo;

void dfs(int node)
{
    int i;
    for (i=last[node];i>=0;i=prev[i])
    if (!viz[target[i]])
    {
        viz[target[i]]=1;
        dfs(target[i]);
    }
}

int main()
{
    int i,x,y,pop,push,cc=0;
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);
    scanf("%d %d",&nodeNo,&edgeNo);
    for (i=0;i<nodeNo;i++) last[i]=-1;
    for (i=0;i<edgeNo;i++)
    {
        scanf("%d %d",&x,&y);x--;y--;
        start[2*i]=x;target[2*i]=y;prev[2*i]=last[x];last[x]=2*i;
        start[2*i+1]=y;target[2*i+1]=x;prev[2*i+1]=last[y];last[y]=2*i+1;
    }
    for (i=0;i<nodeNo;i++)
    if (!viz[i])
    {
        dfs(i);
        cc++;
    }
    printf("%d\n",cc);
    fclose(stdout);
    return 0;
}