#include<bits/stdc++.h>
#define pb emplace_back
using namespace std;
using ll = long long;
const int maxn = 100010;
int x[maxn], y[maxn], L, n;
ll res;
void upsd() {
    for (int i = 0;i < n;++i)
        x[i] = L - x[i] - 1;
}
struct sgt {
    int mn[maxn<<1], sec[maxn<<1], tag[maxn<<1];
    ll sum[maxn<<1], mncnt[maxn<<1];
    void push(int i) {
        if (i < n && tag[i]) {
            node_chmx(i<<1, tag[i]);
            node_chmx(i<<1|1, tag[i]);
            tag[i] = 0;
        }
    }
    void node_chmx(int i, int val) {
        if (i > n+n || mn[i] >= val) return;
        if (val < sec[i]) {
            sum[i] += mncnt[i] * (val - mn[i]);
            mn[i] = val;
            tag[i] = val;
            return;
        }
        tag[i] = max(tag[i], val);
        push(i);
        update(i);
    }
    void update(int i) {
        if (i >= n) return;
        push(i);
        sum[i] = sum[i<<1] + sum[i<<1|1];
        mn[i] = min(mn[i<<1], mn[i<<1|1]), sec[i] = INT_MAX;
        mncnt[i] = (mn[i] == mn[i<<1] ? mncnt[i<<1] : 0) + (mn[i] == mn[i<<1|1] ? mncnt[i<<1|1] : 0);
        for (int v : {mn[i], mn[i<<1|1], sec[i], sec[i<<1|1]})
            if (v > mn[i]) sec[i] = min(sec[i], v);
        if (sec[i] == INT_MAX) sec[i] = mn[i];
    }
    void init() {
        for (int i = 0;i < n;++i) {
            sum[i+n] = mn[i+n] = sec[i+n] = i;
            mncnt[i+n] = 1;
        }
        for (int i = n-1;i > 0;--i)
            update(i);
    }
    void pa(int v) {
        for (int i = 18;i > 0;--i)
            push(v>>i);
    }
    ll getsum(int l, int r) {
        l += n, r += n;
        pa(l), pa(r);
        ll res = 0;
        for (;l < r;l>>=1, r>>=1) {
            if (l&1) res += sum[l++];
            if (r&1) res += sum[--r];
        }
        return res;
    }
    void modify(int i, int v) {
        i += n;
        pa(i);
        sum[i] = mn[i] = sec[i] = v;
        mncnt[i] = 1;
        for (;i>>=1;)
            update(i);
    }
    void chmx(int l, int r, int v) {
        l += n, r += n;
        int sl = l>>1, sr = r>>1;
        for (;l < r;l>>=1, r>>=1) {
            if (l&1) node_chmx(l++, v);
            if (r&1) node_chmx(--r, v);
        }
        for (;sl;sl>>=1, sr>>=1)
            update(sl), update(sr);
    }
}tree;

void solve() {
    vector<vector<int>> mp(L);
    vector<int> vis(L);
    for (int i = 0;i < n;++i)
        mp[x[i]].pb(y[i]);
    ll sum = (n-1) * n / 2;
    ll old = res;
    tree.init();
    cerr << "GS 0 " << tree.getsum(0, n) << '\n';
    cerr << "Sum " << sum << '\n';
    for (int i = 0;i < L;++i, res += sum) {
        for (int u : mp[i]) {
            tree.chmx(u+1, n, u-1);
            tree.modify(u, -1);
        }
        cerr << "getsum at " << i << ' ' << tree.getsum(0, n) << '\n';
        res += sum - tree.getsum(0, n);
        cerr << "Add " << sum - tree.getsum(0, n) << '\n';
    }

    cerr << res -old<< '\n';
    exit(0);
    for (int i = 0;i < L;++i) {
        auto &v = mp[i];
        if (v.size()) res -= L - v.size();//, cerr << " - " << n-v.size() << '\n';
    }
    res -= n;
}

signed main(){
    ios_base::sync_with_stdio(0), cin.tie(0);
    cin >> L >> n;;
    for (int i = 0;i < n;++i)
        cin >> x[i] >> y[i];
    solve();
    upsd();
    solve();
    for (int i = 0;i < n;++i)
        y[i] = L - y[i] - 1;
    solve();
    upsd();
    solve();
    cout << res << '\n';
}