#include <bits/stdc++.h>
#include <fstream>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/trie_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
template<class A, class B>
ostream& operator<<(ostream& o, const pair<A, B>& p) {return o << '(' << p.first << ", " << p.second << ')';}
template<size_t Index = 0, typename... Types>
ostream& printTupleElements(ostream& o, const tuple<Types...>& t) {if constexpr (Index < sizeof...(Types)){if(Index > 0){o << ", ";}o << get<Index>(t);printTupleElements<Index + 1>(o, t);}return o;}
template<typename... Types>
ostream& operator<<(ostream& o, const tuple<Types...>& t){o << "(";printTupleElements(o, t);return o << ")";}
template<class T>
auto operator<<(ostream& o, const T& x) -> decltype(x.end(), o){o << '{';bool first = true;for (const auto& e : x){if (!first){o << ", ";}o << e;first = false;} return o << '}';}
#define DEBUG
#ifdef DEBUG
#define fastio()
#define debug(x...) cerr << "[" #x "]: ", [](auto... $) {((cerr << $ << "; "), ...); }(x), cerr << '\n'
#define check(x) if (!(x)) { cerr << "Check failed: " << #x << " in line " << __LINE__ << endl; exit(1); }
#else
#define fastio() ios_base::sync_with_stdio(0); cin.tie(0);
#define debug(...)
#define check(x) 
#endif
typedef long long ll;
#define pi pair<int, int>
#define pll pair<ll, ll>
#define st first
#define nd second
#define vi vector<int>
#define vll vector<ll>
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size
void solve() {
	//ifstream cin("nazwa.in");
	//ofstream cout("nazwa.out");
	int n;
	cin >> n;
	vector<pi>tab(n);
	for(auto &[x, e] : tab) {
		cin >> x >> e;
	}
	int ans = 1e9;
	for(int mask = 0; mask < (1 << n); mask++) {
		vi czy(n, 0);
		queue<int>q;
		for(int i = 0; i < n; i++) {
			if(mask & (1 << i)) {
				czy[i] = 1;
				q.push(i);
			}
		}
		while(!q.empty()) {
			int kt = q.front();
			q.pop();
			for(int i = 0; i < n; i++) {
				if(!czy[i] && abs(tab[kt].st - tab[i].st) <= tab[kt].nd - tab[i].nd) {
					czy[i] = 1;
					q.push(i);
				}
			}
		}
		int res = 1;
		for(int i = 0; i < n; i++) {
			res &= czy[i];
		}
		if(res) {
			ans = min(ans, __builtin_popcount(mask));
		}
	}
	cout << ans << '\n';
}
int main() {
	fastio();
	int t = 1;
	//cin >> t;
	while(t--) {
		solve();
	}
}