CIRCLES

#define task "CIRCLES"
#include <iostream>
#include <cstdio>
#include <algorithm>
#include <vector>

using namespace std;

using ll = long long;
using ld = long double;

constexpr int N = 1e4 + 5;
constexpr ll Inf = 1e17;
int n, f[N], dp[N], last[N];
struct Circle
{
    ll l, r;
} a[N];

void Read()
{
    cin >> n;

    for (int i = 1; i <= n; ++i)
    {
        ll x, r;
        cin >> x >> r;

        a[i].l = x - r;
        a[i].r = x + r;
    }
}

void Solve()
{
    a[0].l = -Inf;
    a[0].r = Inf;

    sort(a, a + n + 1, [&](const Circle &x, const Circle &y)
         { return x.r < y.r || (x.r == y.r && x.l > y.l); });

    for (int i = 0; i <= n; ++i)
    {
        int l = 0, mid, h = i - 1;
        while (l <= h)
        {
            mid = (l + h) / 2;
            if (a[mid].r <= a[i].l)
                l = mid + 1;
            else
                h = mid - 1;
        }

        last[i] = h;
    }

    for (int i = 0; i <= n; ++i)
    {
        for (int j = 0; j < i; ++j) // assume a[j].r <= a[i].r
            if (a[i].l <= a[j].l)
            {
                dp[j + 1] = dp[j];
                dp[j + 1] = max(dp[j + 1], dp[last[j] + 1] + f[j]);
            }
            else
                dp[j + 1] = dp[j];

        f[i] = dp[i] + 1;
    }

    cout << f[n] - 1;
}

int32_t main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    if (fopen(task ".INP", "r"))
    {
        freopen(task ".INP", "r", stdin);
        freopen(task ".OUT", "w", stdout);
    }

    Read();
    Solve();
}