//*** Bismillah ***//
#pragma GCC optimize("O3", "fast-math", "unroll-loops", "no-stack-protector")
#include <bits/stdc++.h>
using namespace std;
#if !defined(ONLINE_JUDGE) and !defined(EVAL)
#include "template/debug.h"
#else
#define d(x...)
#endif
#define fr first
#define er erase
#define sc second
#define in insert
#define ll long long
#define pb push_back
#define vll vector<ll>
#define pll pair<ll,ll>
#define ull unsigned ll
#define vpll vector<pll>
#define len(x) (ll) x.size()
#define all(x) x.begin(),x.end()
const ll INF = 1e9;
const ll INFL = 1e18;
const ll MOD = 1e9+7;
// const ll MOD = 998244353;
const ll maxn = 2e5+5;
ll n,m,k=0;
ll l[maxn], r[maxn], dp[maxn];
void _(ll &tt){
cin >> n;
ll mx = 0;
for(ll i = 1; i <= n; i ++) cin >> l[i] >> r[i], l[i] = min(l[i], i - 1), r[i] = min(r[i], n - i);
for(ll i = 1; i <= n; i ++){
dp[i] = 1;
for(ll j = 1; j < i; j ++){
if(max(l[i], r[j]) <= i - j - 1){
dp[i] = max(dp[i], dp[j] + 1);
}
}
mx = max(mx, dp[i]);
}
cout << mx << '\n';
}
signed main() {
ll tm = clock();
cin.tie(0)->sync_with_stdio(0);
ll t = 1;
// cin >> t;
for(ll tt = 1; tt <= t; tt ++) {
_(tt);
}
cerr << "\n\033[1;31mTime: \033[1;30m" \
<< (double)(clock()-tm)/1000000 << "\033[1;32m seconds\n";
}
