#include<bits/stdc++.h>
#define pb push_back
#define int long long
#define vi vector<int>
#define vvi vector<vector<int>>
#define vll vector<long long int>
#define vvll vector<vector<long long int>>
#define pii pair<int, int>
#define vpii vector<pair<int, int>>
#define vc vector<char>
#define vvc vector<vector<char>>
#define vb vector<bool>
#define mii map<int,int>
#define mll map<long long int, long long int>
#define mivi map<int,vector<int>>
#define f0r(i,n) for(int i=0;i<n;i++)
#define FOR(i,k,n) for(int i=k;i<n;i++)
using namespace std;
const int mxn = 1005;
vi adj[mxn];
signed main(){
ios::sync_with_stdio(false);
cin.tie(NULL);
//ifstream cin(".in");
//ofstream cout(".out");
int n;
cin>>n;
vpii v(n);
f0r(i, n)cin>>v[i].first>>v[i].second;
int dp[n];
dp[0] = 1;
FOR(i, 1, n){
dp[i] = 1;
f0r(j, i){
if(j + v[j].second < i && i - v[i].first > j)dp[i] = max(dp[i], dp[j] + 1);
}
}
int ans = 0;
f0r(i, n)ans = max(ans, dp[i]);
cout<<ans;
}
