#include <bits/stdc++.h>
using namespace std;
#define ar array
#define ll long long
const int MAX_N = 1e5 + 1;
const int MOD = 1e9 + 7;
const int INF = 1e9;
const ll LINF = 1e18;
inline int readInt() {
int x = 0;
char ch = getchar_unlocked();
while (ch < '0' || ch > '9') ch = getchar_unlocked();
while ('0' <= ch && ch <= '9') {
x = (x << 3) + (x << 1) + ch - '0';
ch = getchar_unlocked();
}
return x;
}
void solve() {
int n = readInt();
stack<ar<int,2>> st;
while (n--) { // increasing x
int x = readInt(), y = readInt();
bool add = true;
while (st.size()) {
auto [tx, ty] = st.top();
if (x - tx <= ty - y) {
add = false;
break;
}
if (x - tx <= y - ty) st.pop();
else break;
}
if (add) st.push({x, y});
}
cout << st.size() << "\n";
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
// freopen("input.txt", "r", stdin);
// freopen("output.txt", "w", stdout);
int tc = 1;
// cin >> tc;
for (int t = 1; t <= tc; t++) {
// cout << "Case #" << t << ": ";
solve();
}
}
