#include <bits/stdc++.h>
#define ll long long
#define ff first
#define ss second
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define pb push_back
#define ertunt return
#define vodka void
#define sleepearly ertunt
using namespace std;
int main() {
ll n;
cin >> n;
vector<ll> l(n),r(n);
for(ll i = 0; i < n; i++)cin >> l[i] >> r[i];
vector<ll>d = r;
sort(all(d));
if(d[d.size() - 1] == 0){
ll lst = -1;
ll ans = 0;
for(ll i = 0; i < n; i++){
if(lst == -1){
ans ++;
lst = i;
continue;
}
if(l[i] < i-lst){
lst = i;
ans++;
}
}
cout << ans << '\n';
ertunt 0;
}
vector<ll>dp(n+5,1);
for(ll i = 0; i < n; i++){
for(ll j = 0; j < i-l[i]; j++){
if(i-j > r[j])dp[i] = max(dp[j]+1,dp[i]);
}
}
cout << *max_element(all(dp));
}
