//#pragma GCC target("avx2")
//#pragma GCC optimization("O3")
//#pragma GCC optimization("unroll-loops")
#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define ff first
#define ss second
#define pb push_back
#define SZ(x) ((int)(x).size())
#define all(x) x.begin(), x.end()
#define debug(x) cout << #x << ": " << x << " "
#define nl cout << "\n"
#define rep(i, a, b) for(int i = (a); i < (b); i++)
#define per(i, a, b) for(int i = (a); i >= (b); i--)
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int fast_read_int(){
register int c, n = 0;
do{
c = getchar_unlocked();
}while (c < '0' || c > '9');
do{
n = (n << 3) + (n << 1) + (c - '0');
c = getchar_unlocked();
}while (c >= '0' && c <= '9');
return n;
}
void solve(){
int N = fast_read_int();
vector<int> x(N), y(N);
rep(i, 0, N){
x[i] = fast_read_int();
y[i] = fast_read_int();
}
deque<int> q;
q.push_back(0);
rep(i, 1, N){
while(SZ(q) && x[i] - y[i] <= x[q.back()] - y[q.back()])
q.pop_back();
q.push_back(i);
}
int ans = 0;
while(SZ(q)){
int v = q[0];
q.front();
ans++;
while(SZ(q) && x[v] + y[v] >= x[q[0]] + y[q[0]]){
q.pop_front();
}
}
cout << ans;
}
int main(){
ios_base::sync_with_stdio(false), cin.tie(nullptr);
solve();
return 0;
}
