using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;
using System.Diagnostics;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static int[][] NArr(long n) => Enumerable.Repeat(0, (int)n).Select(_ => NList).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var n = NN;
        var a = NList;
        var map = NArr(n);
        var ar = new int[n];
        for (var i = 0; i < n; ++i) ar[i] = Math.Min(1_000_000_001, a[i] + map[i][1]);
        var wm = new WaveletMatrix(ar);
        var ans = 0L;
        for (var i = 1; i < n; ++i)
        {
            var pos = LowerBound(0, a[i] - map[i][0], a);
            if (pos < i)
            {
                ans += i - pos - wm.CountLower(pos, i, a[i]);
            }
        }
        WriteLine(ans);
    }
    static int LowerBound(int left, int min, IList<int> list)
    {
        if (list[left] >= min) return left;
        var ng = left;
        var ok = list.Count;
        while (ok - ng > 1)
        {
            var mid = (ng + ok) / 2;
            if (list[mid] < min) ng = mid;
            else ok = mid;
        }
        return ok;
    }
    /// <summary>
    /// WaveletMatrix 初期化時に設定した区間に対して様々な情報を取得するクエリを提供する
    /// </summary>
    class WaveletMatrix
    {
        int n;
        int height;
        int[,] m;
        public WaveletMatrix(int[] _a)
        {
            var a = (int[])_a.Clone();
            n = a.Length;
            var max = 0;
            for (var i = 0; i < n; ++i) max = Math.Max(max, a[i]);
            height = 0;
            var tmp = max;
            while (tmp > 0)
            {
                ++height;
                tmp >>= 1;
            }
            if (height == 0) ++height;
            m = new int[height, n + 1];
            for (var h = height - 1; h >= 0; --h)
            {
                var dir = new List<int>(n);
                var left = new List<int>();
                var right = new List<int>();
                for (var i = 0; i < n; ++i)
                {
                    dir.Add((a[i] >> h) & 1);
                    if (dir[i] == 0) left.Add(a[i]);
                    else right.Add(a[i]);
                }
                for (var i = 0; i < left.Count; ++i) a[i] = left[i];
                for (var i = 0; i < right.Count; ++i) a[i + left.Count] = right[i];
                for (var i = 0; i < n; ++i) m[h, i + 1] = m[h, i] + dir[i];
            }
        }
        (int l0, int r0, int l1, int r1) SubtreeRange(int h, int l, int r)
        {
            var l0 = l - m[h, l];
            var l1 = m[h, l];
            var r0 = r - m[h, r];
            var r1 = m[h, r];
            var c0 = n - m[h, n];
            return (l0, r0, c0 + l1, c0 + r1);
        }
        /// <summary>区間[l,r)からk番目に小さい値を返す kは0-indexed</summary>
        public int KthSmall(int l, int r, int k)
        {
            if (r - l <= k) return -1;
            var ans = 0;
            for (var h = height - 1; h >= 0; --h)
            {
                var one = m[h, r] - m[h, l];
                var zero = r - l - one;
                var (l0, r0, l1, r1) = SubtreeRange(h, l, r);
                ans <<= 1;
                if (zero <= k)
                {
                    l = l1;
                    r = r1;
                    k -= zero;
                    ++ans;
                }
                else
                {
                    l = l0;
                    r = r0;
                }
            }
            return ans;
        }
        /// <summary>区間[l,r)からx未満の値の個数を返す</summary>
        public int CountLower(int l, int r, int x)
        {
            if ((x >> height) != 0) return n;
            var ans = 0;
            for (var h = height - 1; h >= 0; --h)
            {
                var (l0, r0, l1, r1) = SubtreeRange(h, l, r);
                if (((x >> h) & 1) == 0)
                {
                    l = l0;
                    r = r0;
                }
                else
                {
                    l = l1;
                    r = r1;
                    ans += r0 - l0;
                }
            }
            return ans;
        }
    }
}