#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define int long long
#define ll long long
const int maxN = 1e5 + 7;
int d[maxN], x[maxN];
const int MOD = 1e9 + 7;
int n;
int dp[maxN];
void solve() {
cin >> n;
for(int i = 1; i <= n; i++) {
cin >> d[i] >> x[i];
dp[i] = 1;
}
for(int i = n; i >= 1; i--) {
if(d[i] == 0) continue;
for(int j = i + d[i]; j <= min(n, i + d[i] * x[i]); j += d[i]) {
dp[i] += dp[j];
}
}
cout << dp[1] << '\n';
}
signed main() {
//freopen("input.txt", "r", stdin);
ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
int t = 1;
//cin >> t;
while(t--) solve();
}
