#include <bits/stdc++.h>

// #define int int64_t

const int kMaxN = 5e5 + 5;

int n;
int fa[kMaxN];
bool vis[kMaxN];
std::pair<int, int> a[kMaxN];

void dickdreamer() {
  std::cin >> n;
  for (int i = 1; i <= n; ++i) std::cin >> a[i].second >> a[i].first;
  std::sort(a + 1, a + 1 + n);
  n = std::unique(a + 1, a + 1 + n) - (a + 1);
  return void(std::cout << n << '\n');
  int ans = 0;
  for (int i = n; i; --i) {
    if (vis[i]) continue;
    vis[i] = 1, ++ans;
    for (int j = i - 1; j; --j)
      if (abs(a[i].second - a[j].second) <= a[i].first - a[j].first)
        vis[j] = 1;
  }
  std::cout << ans << '\n';
}

int32_t main() {
#ifdef ORZXKR
  freopen("in.txt", "r", stdin);
  freopen("out.txt", "w", stdout);
#endif
  std::ios::sync_with_stdio(0), std::cin.tie(0), std::cout.tie(0);
  int T = 1;
  // std::cin >> T;
  while (T--) dickdreamer();
  // std::cerr << 1.0 * clock() / CLOCKS_PER_SEC << "s\n";
  return 0;
}