#include <stdio.h>
int val[400001],next[400001],last[100001];
char ok[100001];
void dfs(int x){
    int y,poz;
    ok[x]=1;
    poz=last[x];
    while(poz!=0){
        y=val[poz];
        if(ok[y]==0){
            dfs(y);
        }
        poz=next[poz];
    }
}
int main(){
    int n,m,k,i,x,y,s;
    FILE *fin,*fout;
    fin=fopen("dfs.in","r");
    fout=fopen("dfs.out","w");
    fscanf(fin,"%d%d",&n,&m);
    k=0;
    for(i=1;i<=m;i++){
        fscanf(fin,"%d%d",&x,&y);
        k++;
        val[k]=y;
        next[k]=last[x];
        last[x]=k;
        k++;
        val[k]=x;
        next[k]=last[y];
        last[y]=k;
    }
    s=0;
    for(i=1;i<=n;i++){
        if(ok[i]==0){
            dfs(i);
            s++;
        }
    }
    fprintf(fout,"%d\n",s);
    fclose(fin);
    fclose(fout);
    return 0;
}