#include<stdio.h>
using namespace std;

FILE*f=fopen("dfs.in","r");
FILE*g=fopen("dfs.out","w");

struct nod {
    int inf;
    nod *urm;
} *v[100005];

int ni,n,m,s,x,y,i,q[100005],viz[100005],d[100005];

void adaug(nod *&a, int x) {
    nod *p=new nod;
    p->inf=x; p->urm=a;
    a=p;
}

void bf(int x) {
    int p=1,u=1;
    nod *j;
    q[1]=x; viz[x]=1; d[x]=0;
    while(p<=u) {
        for(j=v[x];j!=NULL;j=j->urm)
            if(viz[j->inf]==0) {
                viz[j->inf]=1;
                q[++u]=j->inf;
                d[j->inf]=d[x]+1;
            }
        p++; x=q[p];
    }
}

int main() {
    fscanf(f,"%d%d",&n,&m);

    for(i=1;i<=m;i++) {
        fscanf(f,"%d%d",&x,&y);
        adaug(v[x],y);
        adaug(v[y],x);
    }

    for(i=1;i<=n;i++)
        if(viz[i]==0) {
            bf(i);
            ni++;
        }
    fprintf(g,"%d",ni);

    return 0;
}