#include<stdio.h>
#define N 100001
#define M 200001
long n,m,a1[M],a2[M],c[N],k,i,t;

void dfs(long v)
{c[v]=1;
for(k=1;k<=m;k++)
if(a1[k]==v&&c[a2[k]]==0)
        dfs(a2[k]);
else
        if(a2[k]==v&&c[a1[k]]==0)
                dfs(a1[k]);}

int main()
{freopen("dfs.in","r",stdin);
freopen("dfs.out","w",stdout);
scanf("%ld%ld",&n,&m);
for(k=1;k<=m;k++)
       scanf("%ld%ld",&a1[k],&a2[k]);
for(i=1;i<=n;i++)
       c[i]=0;
t=0;
for(i=1;i<=n;i++)
if(c[i]==0)
       {t++;
       dfs(i);}
printf("%ld\n",t);
fclose(stdin);
fclose(stdout);
return 0;}