#include <bits/stdc++.h>
using namespace std;
int main(){
  long long L, N;
  cin >> L >> N;
  vector<pair<long long, long long>> A, B;
  for (int i = 0; i < N; i++){
    long long y, x;
    cin >> y >> x;
    y--;
    x--;
    if ((x + y) % 2 == 0){
      A.push_back(make_pair(y, x));
    } else {
      B.push_back(make_pair(y, x));
    }
  }
  int Acnt = A.size();
  set<long long> Ax, Ay;
  for (int i = 0; i < Acnt; i++){
    Ay.insert(A[i].first - A[i].second);
    Ax.insert(A[i].first + A[i].second);
  }
  vector<long long> Ay2;
  for (long long y : Ay){
    Ay2.push_back(y);
  }
  long long Aans = 0;
  for (long long x : Ax){
    Aans += min(x + 1, L * 2 - x - 1);
  }
  for (long long y : Ay){
    Aans += L - abs(y);
  }
  for (long long x : Ax){
    long long ub = min(x, L * 2 - 2 - x);
    long long lb = -ub;
    Aans -= upper_bound(Ay2.begin(), Ay2.end(), ub) - lower_bound(Ay2.begin(), Ay2.end(), lb);
  }
  long long Bcnt = B.size();
  set<long long> Bx, By;
  for (int i = 0; i < Bcnt; i++){
    By.insert(B[i].first - B[i].second);
    Bx.insert(B[i].first + B[i].second);
  }
  vector<long long> By2;
  for (long long y : By){
    By2.push_back(y);
  }
  long long Bans = 0;
  for (long long x : Bx){
    Bans += min(x + 1, L * 2 - x - 1);
  }
  for (long long y : By){
    Bans += L - abs(y);
  }
  for (long long x : Bx){
    long long ub = min(x, L * 2 - 2 - x);
    long long lb = -ub;
    Bans -= upper_bound(By2.begin(), By2.end(), ub) - lower_bound(By2.begin(), By2.end(), lb);
  }
  cout << Aans + Bans << endl;
}