#include "bits/stdc++.h"
using namespace std;
#ifdef Nero
#include "Deb.h"
#else
#define debug(...)
#endif
const int B = 50;
const int N = 1e5 + 5;
const int md = (int) 1e9 + 7;
int dp[N];
int d[N], x[N];
int suf[B][B][N];
void add(int& a, int b) {
a += b;
if (a >= md) {
a -= md;
}
}
void sub(int& a, int b) {
a -= b;
if (a < 0) {
a += md;
}
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n;
cin >> n;
for (int i = 0; i < n; ++i) {
cin >> d[i] >> x[i];
}
for (int i = n - 1; i >= 0; --i) {
dp[i] = 1;
if (d[i] >= B) {
for (int j = 1; j <= x[i] && i + d[i] * j < n; ++j) {
add(dp[i], dp[i + d[i] * j]);
}
} else if (d[i] > 0) {
int mod = i % d[i];
if (i + d[i] < n) {
add(dp[i], suf[d[i]][mod][i + d[i]]);
}
if ((long long) d[i] * (x[i] + 1) + i < n) {
sub(dp[i], suf[d[i]][mod][i + d[i] * (x[i] + 1)]);
}
}
for (int cd = 1; cd < B; ++cd) {
suf[cd][i % cd][i] = dp[i];
if (i + cd < n) {
add(suf[cd][i % cd][i], suf[cd][i % cd][i + cd]);
}
}
}
cout << dp[0] << '\n';
return 0;
}
