#include <cstdio>
#include <cstdlib>
#define N 100001
using namespace std;

int n, m;
int *g[N], deg[N], v[N], mc[2*N][2];

void dfs(int x)
{
    int *p;
    v[x]=1;
    for(p=g[x];*p!=-1;p++)
    {
        if(!v[*p])
        {
            dfs(*p);
        }
    }
}

int main()
{
    freopen("dfs.in", "r", stdin);
    freopen("dfs.out", "w", stdout);
    int i, j;
    long long sol=0;
    scanf("%d%d", &n, &m);
    for(i=1;i<=m;i++)
    {
        scanf("%d%d", &mc[i][0], &mc[i][1]);
        deg[mc[i][0]]++;deg[mc[i][1]]++;
    }
    for(i=1;i<=n;i++)
    {
        g[i]=(int *) malloc((deg[i]+1)*sizeof(int));
        g[i][deg[i]]=-1;
        deg[i]=0;
    }
    for(;m;m--)
    {
        i=mc[m][0];j=mc[m][1];
        //printf("%d %d\n", i, j);
        g[i][deg[i]++]=j;
        g[j][deg[j]++]=i;
    }
    for(i=1;i<=n;i++)
    {
        if(!v[i])
        {
            dfs(i);
            sol++;
        }
    }
    printf("%lld", sol);
}