#include <bits/stdc++.h>
using namespace std;
#define lf "\n"
#define ff endl
#define _ << ' ' <<
#define all(x) begin(x),end(x)
#define rall(x) rbegin(x),rend(x)
#define infos(str) do { fprintf(stderr, str"\n"); } while(0)
#define infor(str, ...) do { fprintf(stderr, str, __VA_ARGS__); } while(0)
#define infof(str, ...) do { fprintf(stderr, str"\n", __VA_ARGS__); } while(0)
#ifndef DEBUG
#undef infos
#undef infor
#undef infof
#define infos(str)
#define infor(str, ...)
#define infof(str, ...)
#endif
using ll = long long;
constexpr int LOG = 20;
constexpr int MOD = 1e9+7;
constexpr int MAXN = 1e5+7;
int main(void) {
ios::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
int N; cin >> N;
vector<array<int, 2>> V(N);
for(int i = 0; i < N; ++i) {
auto &[l, r] = V[i];
cin >> l >> r;
l = max(0, i - l);
r = min(i + r, N);
}
int ans = 1;
vector<int> dp(N, 1);
for(int i = 0; i < N; ++i) {
for(int j = V[i][1] + 1; j < N; ++j) {
if(V[j][0] <= i) continue;
dp[j] = max(dp[j], 1 + dp[i]);
}
ans = max(ans, dp[i]);
}
cout << ans << lf;
}
