#include <iomanip>
#include <iostream>
#include <functional>
#include <algorithm>
using namespace std;

//20000000 10000000

long long x[300000];

long long y[300000];
int f[300000];
int factor(int x){

	return x*x - (x*(x + 1)) / 2;;

}
int main(){
	int n;

	cin >> n;
	long long k = 0;
	for (int i = 0; i < n; i++){
		cin >> x[i];
		cin >> y[i];
	}
	int t[300000];
	for (int i = 0; i < 2500; i++){

		t[i] = 0;
	}
	for (int i = 0; i < n; i++){

		f[i] = y[i] - x[i];

	}
	sort(f, f + n);
	int j = 0;
	for (int i = 0; i < n - 1; i++){
		if (f[i] == f[i + 1]){
			t[j] = t[j]++;

		}
		else j++;
	}
	long long g = 0;
	for (int i = 0; i <= j; i++){
		g = g + factor(t[i] + 1);
	}


	for (int i = 0; i < n; i++){
		y[i] = -y[i];


	}for (int i = 0; i < n; i++){

		f[i] = y[i] - x[i];

	}
	sort(f, f + n);
	j = 0;
	for (int i = 0; i < 2000; i++){

		t[i] = 0;
	}
	for (int i = 0; i < n - 1; i++){
		if (f[i] == f[i + 1]){
			t[j] = t[j]++;

		}
		else j++;
	}

	for (int i = 0; i <= j; i++){
		g = g + factor(t[i] + 1);
	}





	cout << g;



}