#include <cstdio>
#include <vector>
#define NMAX 100010
using namespace std;
int n,m,i,x,y,sol;
vector <int> G[NMAX];
bool ok[NMAX];

void dfs(int node)
{
    int i,s,x;
    s=G[node].size();
    ok[node]=true;
    for(i=0; i<s; ++i)
    {
        x=G[node][i];
        if(!ok[x])
            dfs(x);
    }
    return;
}

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].push_back(y);
        G[y].push_back(x);
    }
    for(i=1; i<=n; ++i)
        if(!ok[i])
        {
            ++sol;
            dfs(i);
        }
    printf("%d\n",sol);
    return 0;
}