/**
 *    author:  zjsdut
 *    created: 2020/01/18 20:07:15
**/
#include <bits/stdc++.h>

using namespace std;

struct fast_ios {
    fast_ios() {
        cin.tie(nullptr);
        ios::sync_with_stdio(false);
        cout << fixed << setprecision(10);
    };
} fast_ios_;

template<typename A, typename B>
bool chkmin(A &a, const B &b) {
    if (b < a) {
        a = b;
        return true;
    }
    return false;
}

template<typename A, typename B>
bool chkmax(A &a, const B &b) {
    if (b > a) {
        a = b;
        return true;
    }
    return false;
}

template<typename T>
istream &operator>>(istream &stream, vector<T> &vec) {
    for (auto &x : vec) stream >> x;
    return stream;
}

void scan() {}

template<class T, class ...Args>
void scan(T &a, Args &...rest) {
    cin >> a;
    scan(rest...);
}

using ll = long long;
using vl = vector<ll>;
using vb = vector<bool>;
using vi = vector<int>;
using pii = pair<int, int>;
template<typename T> using vv = vector<vector<T>>;
#define rng(i, a, b) for(int i = (int)(a); i < (int)(b); ++i)
#define up(i, a, b) for (int i = int(a); i <= int(b); ++i)
#define down(i, b, a) for (int i = int(b); i >= int(a); i--)
#define rep(n) for(int _iter_##n = 0, _num_##n = (int)n; _iter_##n < _num_##n; ++_iter_##n)
#define FOR(x, cont) for (const auto &x: cont)
#define For(x, cont) for (auto &x: cont)
#define all(x) begin(x), end(x)
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define ep emplace
#define SZ(x) (int)(x).size()
#define UNIQ(vec) (vec).erase(unique(all(vec)), end(vec))
#define LB(cont, x) int(lower_bound(all(cont), x) - begin(cont))
#define UB(cont, x) int(upper_bound(all(cont), x) - begin(cont))

template<typename T>
ostream &operator<<(ostream &stream, const vector<T> &vec) {
    if (!vec.empty()) {
        stream << vec[0];
        for (size_t i = 1; i != vec.size(); ++i)
            stream << ' ' << vec[i];
    }
    return stream;
}

template<typename T>
void print(const vector<T> &t) { cout << t << '\n'; }

template<typename T>
void print(const vector<vector<T>> &t) {
    for (const auto &row : t) {
        print(row);
    }
}

template<typename T>
void print(const T &t) { cout << t << ' '; }

template<typename T, typename ...Args>
void print(const T &t, const Args &...rest) {
    print(t);
    print(rest...);
}

template<typename T>
void println(const T &t) { cout << t << '\n'; }

template<typename T, typename ...Args>
void println(const T &t, const Args &...rest) {
    print(t);
    println(rest...);
}

// debug code by tourist
string to_string(const string &s) {
    return '"' + s + '"';
}

string to_string(const char *s) {
    return to_string((string) s);
}

string to_string(bool b) {
    return (b ? "true" : "false");
}

template<typename A, typename B>
string to_string(pair<A, B> p) {
    return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}

template<typename A>
string to_string(A v) {
    bool first = true;
    string res = "{";
    for (const auto &x : v) {
        if (!first) {
            res += ", ";
        }
        first = false;
        res += to_string(x);
    }
    res += "}";
    return res;
}

void debug_out() { cerr << endl; }

template<typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
    cerr << " " << to_string(H);
    debug_out(T...);
}

#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif

int main() {
#if defined LOCAL
    ifstream in("in.txt");
    cin.rdbuf(in.rdbuf());
#endif
    int n;
    scan(n);
    vector<pii> a(n);
    rng (i, 0, n) {
        int x, l;
        scan(x, l);
        a[i] = {x - l, x + l};
    }
    sort(all(a));
    debug(a);
    vector<pii> b;
    rng (i, 0, n) {
        if (b.empty()) {
            b.pb(a[i]);
        } else {
            if (a[i].first == a[i - 1].first) {
                continue;
            } else {
                if (a[i].first >= b.back().second) {
                    b.pb(a[i]);
                } else if (a[i].second < b.back().second){
                    b.pop_back();
                    b.push_back(a[i]);
                }
            }
        }
    }
    println(SZ(b));
    return 0;
}

Measured memory_bytes: 2168