#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll mod = 1e9 + 7;
int main()
{
ios::sync_with_stdio(0);
cin.tie(0);
ll N; cin >> N;
const ll sqrtN = sqrt(N);
// DP forward or backwards?
// d[i] > sqrtN - DP forward
ll res = 0;
vector<vector<ll>> fw(N, vector<ll>(sqrtN + 1));
vector<ll> DP(N);
DP[0] = 1;
for (ll i = 0; i < N; i++)
{
ll d, x;
cin >> d >> x;
for (int j = 1; j <= sqrtN; j++)
{
DP[i] = (DP[i] + fw[i][j]) % mod;
}
for (int j = 1; j <= sqrtN; j++)
{
if (i + j >= N)
break;
fw[i+j][j] = (fw[i+j][j] + fw[i][j]) % mod;
}
res = (res + DP[i]) % mod;
if (d > sqrtN)
{
ll next = i + d;
int t = 0;
while (next <= N-1ll && t < x)
{
DP[next] = (DP[next] + DP[i]) % mod;
next += d; t++;
}
}
else // d <= sqrtN
{
if (i + d >= N || d == 0)
continue;
fw[i+d][d] = (fw[i+d][d] + DP[i]) % mod;
ll last = i + (x + 1ll) * d;
if (last >= N)
continue;
fw[last][d] = (mod + fw[last][d] - DP[i]) % mod;
}
}
cout << res << '\n';
return 0;
}
