#include <cstdio>
#include <vector>
#include <bitset>
#define MAX_N 100000

using namespace std;

vector<int>v[MAX_N+5];
bitset<MAX_N+5>f;

void dfs(int nod){
    int k;
    while (!v[nod].empty()){
        k=v[nod].back();
        if (!f[k]){
            f[k]=1;
            v[nod].pop_back();
            dfs(k);
        }else
            v[nod].pop_back();
    }
}

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