#include"bits/stdc++.h"
using namespace std;
#define REP(k,m,n) for(int (k)=(m);(k)<(n);(k)++)
#define rep(i,n) REP((i),0,(n))
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using tp3 = tuple<int, int, int>;
using Mat = vector<vector<ll>>;
constexpr int INF = 1 << 28;
constexpr ll INFL = 1ll << 60;
constexpr int dh[4] = { 0,1,0,-1 };
constexpr int dw[4] = { -1,0,1,0 };
bool isin(const int H, const int W, const int h, const int w) {
    return 0 <= h && h < H && 0 <= w && w < W;
}
// ============ template finished ============

int main()
{
    ll N, M;
    cin >> N >> M;
    set<ll> vals;
    map<ll, vector<ll>> rev;
    rep(i, M) {
        ll B, C;
        cin >> B >> C;
        vals.insert(C);
        rev[C].push_back(B);
    }
    map<ll, ll> id2mp;
    for (auto val : vals)id2mp[val] = val;
    {
        auto itr = vals.end();
        do {
            --itr;
            for (auto next : rev[*itr]) {
                id2mp[next] = max(id2mp[next], id2mp[*itr]);
            }
        } while (itr != vals.begin());
    }

    ll res = 0;
    REP(i, 1, N + 1) {
        ll tres = id2mp.find(i) == id2mp.end() ? i : id2mp.at(i);
        res += max(tres, (ll)i);
    }
    cout << res << endl;
    return 0;
}