#include<cstdio>
#include<deque>
#include<vector>
using namespace std;
#define N 100002
int u[N],k=0;
vector<int> v[N];

void dfs(int x)
{
    for(int i=0;i<v[x].size();i++)
    {
        if(u[v[x][i]]==0)
        {
            u[v[x][i]]=k;
            dfs(v[x][i]);
        }
    }
}

int main()
{
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);
    int n,m,x,y,i;
    scanf("%d%d",&n,&m);
    for(i=0;i<m;i++)
    {
        scanf("%d%d",&x,&y);
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for(i=1;i<=n;i++)
    {
        if(u[i]==0)
        {
            k++;
            u[i]=k;
            dfs(i);
        }
    }
    printf("%d\n",k);
    //for(i=1;i<=n;i++)
    //    printf("%d ",u[i]);
    return 0;
}