#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N = 1e5 + 5;
const int MOD = 1e9 + 7;
const int Root = 300 + 5;
pair<int, int> Trains[N];
int DP[N];
int Helper[Root][Root];
vector<int> Events[N];
int Solve(int n)
{
DP[0] = 1;
int sol = 0;
for(int i = 0; i < n; i++) {
for(int j = 1; j < Root; j++) {
int idx = i % j;
DP[i] = (DP[i] + Helper[j][idx]) % MOD;
}
if(Trains[i].first > 0 && Trains[i].first < Root) {
int idx = i % Trains[i].first;
Helper[Trains[i].first][idx] = (Helper[Trains[i].first][idx] + DP[i]) % MOD;
int lim = i + Trains[i].first * Trains[i].second;
if(lim < n)
Events[lim].push_back(i);
} else if(Trains[i].first > 0) {
for(int j = 1; j <= Trains[i].second; j++) {
int pos = i + j*Trains[i].first;
if(pos >= n)
break;
DP[pos] = (DP[pos] + DP[i]) % MOD;
}
}
for(auto e : Events[i]) {
int idx1 = Trains[e].first, idx2 = e % Trains[e].first;
Helper[idx1][idx2] = ((Helper[idx1][idx2] - DP[e]) % MOD + MOD) % MOD;
}
sol = (sol + DP[i]) % MOD;
}
return sol;
}
int32_t main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
int n;
cin >> n;
for(int i = 0; i < n; i++)
cin >> Trains[i].first >> Trains[i].second;
cout << Solve(n) << "\n";
return 0;
}
