#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#define ll long long
#define pll pair<ll, ll>
#define pii pair<int, int>
#define coutpair(p) cout << p.first << " " << p.second << "\n"
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
typedef tree<int, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_multiset;
inline int readInt() {
int x = 0;
char ch = getchar_unlocked();
bool s = 1;
while (ch < '0' || ch > '9') {
if (ch == '-') {
s = 0;
ch = getchar_unlocked();
}
}
while (ch >= '0' && ch <= '9') {
x = (x << 3) + (x << 1) + ch - '0';
ch = getchar_unlocked();
}
return s ? x : -x;
}
stack<pii> s;
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n = readInt();
for (int i=0; i<n; i++){
int x = readInt();
int y = readInt();
bool add = true;
while (s.size()) {
int fx = s.top().first;
int fy = s.top().second;
if (x-fx <= fy-y) {
add = false;
break;
}
if (x-fx <= y-fy) {
s.pop();
}
else break;
}
if (add) s.push({x, y});
}
cout << s.size();
return 0;
}
