#include <bits/stdc++.h>
using namespace std;
bool checkbit(int mask, int bit) { return ((mask >> bit) & 1) == 1; }
int bitscnt(int mask) {
  int res = 0;
  while (mask) {
    if (mask & 1) res++;
    mask >>= 1;
  }
  return res;
}
template <typename T>
inline T sqr(T x) {
  T x_ = (x);
  return x_ * x_;
}
template <typename T>
inline T qbr(T x) {
  T x_ = (x);
  return x_ * x_ * x_;
}
template <typename T>
inline int sign(T x) {
  T x_ = (x);
  return ((x_ > T(0)) - (x_ < T(0)));
}
template <typename T>
inline T mod(T x, T m) {
  T x_ = (x);
  return (((x_) >= 0) ? ((x_) % (m)) : ((((x_) % (m)) + (m)) % (m)));
}
template <typename T>
inline T gcd(T a, T b) {
  while (b) {
    T t = a % b;
    a = b;
    b = t;
  }
  return a;
}
template <typename T>
inline T gcd_ex(T a, T b, T& x, T& y) {
  if (b == 0) {
    x = 1, y = 0;
    return a;
  }
  T x1, y1;
  T d = gcd_ex(b, a % b, x1, y1);
  x = y1;
  y = x1 - (a / b) * y1;
  return d;
}
template <typename T>
inline T lcm(T a, T b) {
  return (a * (b / gcd(a, b)));
}
template <typename T>
inline T binpow(T x, T deg) {
  T res = (T)1;
  for (; deg; x *= x, deg >>= 1)
    if (deg & 1) res *= x;
  return res;
}
template <typename T>
inline T modpow(T x, T deg, T m) {
  assert(deg >= (T)0);
  T res = (T)(1);
  for (; deg; x = mod(mod(x, m) * mod(x, m), m), deg >>= 1)
    if (deg & 1) res = mod(mod(res, m) * mod(x, m), m);
  return res;
}
template <class T1, class T2>
istream& operator>>(istream& in, pair<T1, T2>& P) {
  in >> P.first >> P.second;
  return in;
}
template <class T>
istream& operator>>(istream& in, vector<T>& Col) {
  for (auto& el : Col) in >> el;
  return in;
}
template <class T1, class T2>
ostream& operator<<(ostream& os, const pair<T1, T2>& p) {
  os << "(" << p.first << ", " << p.second << ")";
  return os;
}
template <class T>
ostream& operator<<(ostream& os, const vector<vector<T>>& v) {
  for (auto& row : v) {
    for (auto& el : row) os << el << " ";
    os << "\n";
  }
  return os;
}
template <class T>
ostream& operator<<(ostream& os, const vector<T>& Col) {
  for (auto& el : Col) os << el << " ";
  return os;
}
template <class T>
ostream& operator<<(ostream& os, const set<T>& Col) {
  for (auto& el : Col) os << el << " ";
  return os;
}
template <class T1, class T2>
ostream& operator<<(ostream& os, const map<T1, T2>& Col) {
  for (auto& el : Col) os << el << " ";
  return os;
}
map<long long, long long> m[2];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) {
    int x, y;
    cin >> x >> y;
    m[0][x + y]++;
    m[1][x - y]++;
  }
  long long ans = 0;
  for (int i = -1000; i <= 2000; i++) {
    ans += m[0][i] * (m[0][i] - 1);
    ans += m[1][i] * (m[1][i] - 1);
  }
  cout << ans / 2 << '\n';
  return 0;
}
