#include <iostream>
#include <vector>
#include <queue>

template <class Cost = int>
struct Edge {
    int src, dst;
    Cost cost;
    Edge(int src = -1, int dst = -1, Cost cost = 1)
        : src(src), dst(dst), cost(cost){};

    bool operator<(const Edge<Cost>& e) const { return this->cost < e.cost; }
    bool operator>(const Edge<Cost>& e) const { return this->cost > e.cost; }
};

template <class Cost = int>
using Edges = std::vector<Edge<Cost>>;

template <class Cost = int>
struct Graph {
    std::vector<std::vector<Edge<Cost>>> graph;

    Graph(int n = 0) : graph(n) {}

    void span(bool direct, int src, int dst, Cost cost = 1) {
        graph[src].emplace_back(src, dst, cost);
        if (!direct) graph[dst].emplace_back(dst, src, cost);
    }

    int size() const { return graph.size(); }
    void clear() { graph.clear(); }
    void resize(int n) { graph.resize(n); }

    std::vector<Edge<Cost>>& operator[](int v) { return graph[v]; }
    std::vector<Edge<Cost>> operator[](int v) const { return graph[v]; }
};

using lint = long long;

void solve() {
    int n, m;
    std::cin >> n >> m;

    Graph<> graph(n);
    while (m--) {
        int u, v;
        std::cin >> u >> v;
        graph.span(true, --v, --u);
    }

    std::vector<int> to(n, -1);
    for (int x = n - 1; x >= 0; --x) {
        if (to[x] != -1) continue;

        to[x] = x;
        std::queue<int> que;
        que.push(x);

        while (!que.empty()) {
            int v = que.front();
            que.pop();

            for (auto e : graph[v]) {
                int u = e.dst;
                if (to[u] != -1) continue;
                to[u] = x;
                que.push(u);
            }
        }
    }

    lint ans = 0;
    for (auto x : to) ans += x + 1;
    std::cout << ans << "\n";
}

int main() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    solve();

    return 0;
}