#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
const ll LOG = 31;
const ll MOD = 1000000007;
const ll inf = 1e17;
const ll B = 2305843009213693951;
#define f first
#define s second
#define db(x) cerr << #x << " = " << x << " | "
#define dbg(x) cerr << #x << " = " << x << "\n"
#define Algerian ios::sync_with_stdio(0);
#define OI cin.tie(NULL);
struct segtree {
ll n;
vector<ll> tree;
segtree(ll N) {
n = N;
tree.assign(2 * n, 0);
}
void update(ll p, ll x) {
p += n;
tree[p] = x;
for (p >>= 1; p > 0; p >>= 1) {
tree[p] = max(tree[p << 1], tree[p << 1 | 1]);
}
}
ll mx(ll l, ll r) {
ll res = 0;
for (l += n, r += n; l <= r; l >>= 1, r >>= 1) {
if (l & 1) res = max(res, tree[l++]);
if (!(r & 1)) res = max(res, tree[r--]);
}
return res;
}
};
int main() {
Algerian OI
ll n;
cin >> n;
vector<pll> a(n + 1);
for (ll i = 1; i <= n; i++) {
cin >> a[i].f >> a[i].s;
a[i].f = min(a[i].f, i - 1);
a[i].s = min(a[i].s, n - i);
}
vector<vector<ll>> dp(n + 1, vector<ll>(2));
vector<vector<ll>> update(n + 1);
for (ll i = 1; i <= n; i++) {
ll l = i - a[i].f;
update[l - 1].push_back(i);
}
segtree seg(n + 1);
for (ll i = 0; i <= n; i++) {
seg.update(i + a[i].s, dp[i][1]);
if (i > 0) dp[i][0] = max(dp[i][0], max(dp[i - 1][0], dp[i - 1][1]));
// dbg(dp[i]);
// if (i < n) dp[i + 1] = max(dp[i + 1], dp[i]);
for (ll x : update[i]) {
dp[x][1] = max(dp[x][1], seg.mx(0, x - 1) + 1);
}
}
cout << max(dp[n][1], dp[n][0]) << "\n";
return 0;
}
