#include<cstdio>
using namespace std;
int a[2000][2000];
bool viz[2000];
int n,m;
void dfs(int x)
{
    int i;
    viz[x]=1;
    for(i=1;i<=n;i++)
        if(viz[i]==0 && a[x][i]==1)
            dfs(i);
}
int main()
{
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);
    int i,x,y;
    scanf("%d %d",&n,&m);
    int lc=0;
    for(int i=1;i<=m;i++)
    {
        scanf("%d %d",&x,&y);
        a[x][y]=a[y][x]=1;
    }
    for(i=1;i<=n;i++)
        if(viz[i]==0)
        {
            lc++;
            dfs(i);
        }
    printf("%d\n",lc);
    return 0;
}