#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;
#ifdef _debug
#include </home/tony/templates/debug.cpp>
#else
#define debug(...) 42
#endif
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define pb push_back
#define vi vector<int>
#define vt vector
#define all(x) x.begin(), x.end()
#define sz(x) (int)x.size()
mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
const int MOD = 1e9 + 7, inf = (int)2e9;
const ll infll = (ll)1e18;
void solve(){
int N; cin >> N;
vector<int> dp(N+1); //dp[i] -> answer is i choose i as the last tulip
vector<int> l(N+1), r(N+1);
for(int i = 1; i <= N; i++)cin >> l[i] >> r[i];
for(int i = 1; i <= N; i++){
dp[i] = 1;
for(int j = 1; j < i; j++){
if(j + r[j] < i && i - l[i] > j){
dp[i] = max(dp[i], dp[j+1]+1);
}
}
}
cout << *max_element(all(dp)) << '\n';
}
int main(){
ios_base::sync_with_stdio(false); cin.tie(0);
solve();
}
