#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define int long long
#define FOR(i, a, b) for (int i = (a); i <= (b); i++)
#define FORD(i, a, b) for (int i = (b); i >= (a); i --)
#define REP(i, a) for (int i = 0; i < (a); ++i)
#define REPD(i, a) for (int i = (a) - 1; i >= 0; --i)
#define MASK(i) (1LL << (i))
#define BIT(x, i) (((x) >> (i)) & 1)
constexpr ll LINF = (1ll << 60);
constexpr int INF = (1ll << 30);
constexpr int Mod = 1e9 + 7;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
/*
Phu Trong from Nguyen Tat Thanh High School for gifted student
*/
template <class X, class Y>
bool minimize(X &x, const Y &y){
X eps = 1e-9;
if (x > y + eps) {x = y; return 1;}
return 0;
}
template <class X, class Y>
bool maximize(X &x, const Y &y){
X eps = 1e-9;
if (x + eps < y) {x = y; return 1;}
return 0;
}
int numHouse;
#define MAX 10000005
pair<int, int> P[MAX];
bool cover(pair<int, int> i, pair<int, int> j){
return abs(i.first - j.first) <= i.second - j.second;
}
void process(void){
cin >> numHouse;
for (int i = 1; i <= numHouse; ++i) {
cin >> P[i].first >> P[i].second;
}
stack<int> st;
for (int i = 1; i <= numHouse; ++i){
while(st.size() && cover(P[i], P[st.top()])) st.pop();
if (st.empty() || !cover(P[st.top()], P[i])){
st.push(i);
}
}
cout << (int)st.size();
}
signed main(){
#define name "Whisper"
cin.tie(nullptr) -> sync_with_stdio(false);
//freopen(name".inp", "r", stdin);
//freopen(name".out", "w", stdout);
process();
return (0 ^ 0);
}
