#include <cstdio>
#include<vector>
using namespace std;
int nr,i,j,n,m,x,y,v[100003];
vector<int>a[100003];

void dfs(int i)
{
    v[i]=1;
    while(!a[i].empty())
    {
        if(!v[a[i].back()])
            dfs(a[i].back());
        a[i].pop_back();
    }
}

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);
        a[x].push_back(y);
        a[y].push_back(x);
    }
    for(i=1;i<=n;i++)

        if(!v[i])
        {
            nr++;
            dfs(i);
        }
    printf("%d\n",nr);
    return 0;
}