# include <cstdio>
# include <bitset>
using namespace std;
int n,m,i,k,viz[100001],x,y;
bitset <10001>G[10001];
void DFS(int x)
{
    int i;
    viz[x]=1;
    for(i=1;i<=n;++i)
        if(!viz[i]&&G[x][i]==1)DFS(i);
}
int main()
{
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);
    scanf("%d%d",&n,&m);
    for(i=1;i<=m;++i)
    {
        scanf("%d%d",&x,&y);
        G[x][y]=G[y][x]=1;
    }
    for(i=1;i<=n;++i)
        if(!viz[i])
        {
            k++;
            DFS(i);
        }
    printf("%d\n",k);
    return 0;
}