#include <iostream>
#include <string>
#include <sstream>
#include <stack>
#include <algorithm>
#include <cmath>
#include <queue>
#include <bitset>
#include <iomanip>
#include <limits>
#include <chrono>
#include <random>
#include <array>
#include <unordered_map>
#include <functional>
#include <complex>
#include <numeric>
#include <cctype>
#include <map>
#include <set>
#include <cstdlib>
#include <bitset>
#include <tuple>
#include <assert.h>
#include <deque>
#include <utility>
#include <fstream>

using namespace std;
typedef long long ll;

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
template<typename T> T gcd(T a, T b) { a = abs(a), b = abs(b); while (b > 0) { tie(a, b) = make_pair(b, a % b); } return a; }
//mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());

constexpr long long INF = 1LL << 60;
constexpr int inf = 1000000007;
//constexpr long long mod = 1000000007LL;
//constexpr long long mod = 998244353;
constexpr int MAX = 5000000;

ll f(ll a, ll b) {
	return min(a, b);
}

ll g(ll a, ll b) {
	return min(a, b);
}

ll h(ll a, ll b) {
	return min(a, b);
}
template< typename Monoid, typename OperatorMonoid = Monoid >
struct LazySegmentTree {
	/*
	using F = function< Monoid(Monoid, Monoid) >;
	using G = function< Monoid(Monoid, OperatorMonoid) >;
	using H = function< OperatorMonoid(OperatorMonoid, OperatorMonoid) >;
	*/
	int sz, height;
	vector< Monoid > data;
	vector< OperatorMonoid > lazy;
	/*
	const F f;
	const G g;
	const H h;
	*/
	const Monoid M1;
	const OperatorMonoid OM0;


	LazySegmentTree(int n, /*const F f, const G g, const H h,*/
		const Monoid& M1, const OperatorMonoid OM0)
		: /*f(f), g(g), h(h),*/ M1(M1), OM0(OM0) {
		sz = 1;
		height = 0;
		while (sz < n) sz <<= 1, height++;
		data.assign(2 * sz, M1);
		lazy.assign(2 * sz, OM0);
	}

	void set(int k, const Monoid& x) {
		data[k + sz] = x;
	}

	void build() {
		for (int k = sz - 1; k > 0; k--) {
			data[k] = f(data[2 * k + 0], data[2 * k + 1]);
		}
	}

	inline void propagate(int k) {
		if (lazy[k] != OM0) {
			lazy[2 * k + 0] = h(lazy[2 * k + 0], lazy[k]);
			lazy[2 * k + 1] = h(lazy[2 * k + 1], lazy[k]);
			data[k] = reflect(k);
			lazy[k] = OM0;
		}
	}

	inline Monoid reflect(int k) {
		return lazy[k] == OM0 ? data[k] : g(data[k], lazy[k]);
	}

	inline void recalc(int k) {
		while (k >>= 1) data[k] = f(reflect(2 * k + 0), reflect(2 * k + 1));
	}

	inline void thrust(int k) {
		for (int i = height; i > 0; i--) propagate(k >> i);
	}

	void update(int a, int b, const OperatorMonoid& x) {
		if (a >= b) return;
		thrust(a += sz);
		thrust(b += sz - 1);
		for (int l = a, r = b + 1; l < r; l >>= 1, r >>= 1) {
			if (l & 1) lazy[l] = h(lazy[l], x), ++l;
			if (r & 1) --r, lazy[r] = h(lazy[r], x);
		}
		recalc(a);
		recalc(b);
	}

	Monoid query(int a, int b) {
		if (a >= b) return M1;
		thrust(a += sz);
		thrust(b += sz - 1);
		Monoid L = M1, R = M1;
		for (int l = a, r = b + 1; l < r; l >>= 1, r >>= 1) {
			if (l & 1) L = f(L, reflect(l++));
			if (r & 1) R = f(reflect(--r), R);
		}
		return f(L, R);
	}

	Monoid operator[](const int& k) {
		return query(k, k + 1);
	}

};


int main()
{

	cin.tie(nullptr);
	ios::sync_with_stdio(false);

	ll n, kkt; cin >> n >> kkt;
	ll res = (n - 2) * (n - 2);

	LazySegmentTree<ll, ll> lh(n, INF, INF), lw(n, INF, INF);
	for (int i = 0; i < n; i++) {
		lh.set(i, n - 2);
		lw.set(i, n - 2);
	}
	lh.build();
	lw.build();
	while (kkt--) {
		ll h, w; cin >> h >> w;
		h--; w--;
		if (h == 0) {
			ll mn = lh.query(w, w + 1);
			res -= mn;
			lw.update(0, mn + 1, w - 1);
		}
		else {
			ll mn = lw.query(w, w + 1);
			res -= mn;
			lh.update(0, mn + 1, w - 1);
		}
		//cout << res << endl;
	}
	cout << res << endl;
	return 0;
}


Measured memory_bytes: 19560