#include <bits/stdc++.h>
#define fo(i, d, c) for (int i = d; i <= c; i++)
#define fod(i, c, d) for (int i = c; i >= d; i--)
#define maxn 1000010
#define N 1010
#define fi first
#define se second
#define pb emplace_back
#define en cout << "\n";
#define int long long
#define inf (int)1e18
#define bitcount(x) __builtin_popcountll(x)
#define pii pair<int, int>
#define vii vector<pii>
#define lb(x) x & -x
#define bit(i, j) ((i >> j) & 1)
#define offbit(i, j) (i ^ (1LL << j))
#define onbit(i, j) (i | (1LL << j))
#define vi vector<int>
#define all(x) x.begin(), x.end()
#define ss(x) (int)x.size()
template <typename T1, typename T2>
bool minimize(T1 &a, T2 b)
{
if (a > b)
{
a = b;
return true;
}
return false;
}
template <typename T1, typename T2>
bool maximize(T1 &a, T2 b)
{
if (a < b)
{
a = b;
return true;
}
return false;
}
using namespace std;
const int nsqrt = 580;
const int mod = 1e9 + 7;
void add(int &x, int k)
{
x += k;
x %= mod;
if (x < 0)
x += mod;
}
void del(int &x, int k)
{
x -= k;
x %= mod;
if (x < 0)
x += mod;
}
int n;
vi event[maxn];
int a[maxn], b[maxn];
int save[N][N];
int f[maxn];
void calc(int x)
{
fo(i, 1, nsqrt)
{
add(f[x], save[i][x % i]);
}
}
void bigup(int x)
{
for (int i = x + a[x]; i <= min(n, x + b[x] * a[x]); i += a[x])
{
add(f[i], f[x]);
}
}
void smallup(int x)
{
add(save[a[x]][x % a[x]], f[x]);
if (x + (b[x] + 1) * a[x] <= n)
event[x + (b[x] + 1) * a[x]].pb(x);
}
void rev(int x)
{
for (auto it : event[x])
{
del(save[a[it]][it % a[it]], f[it]);
}
}
main()
{
#define name "trains"
if (fopen(name ".inp", "r"))
{
freopen(name ".inp", "r", stdin);
freopen(name ".out", "w", stdout);
}
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> n;
fo(i, 1, n) cin >> a[i] >> b[i];
f[1] = 1;
fo(i, 1, n)
{
rev(i);
calc(i);
if (a[i] > nsqrt)
bigup(i);
else if (a[i] > 0)
smallup(i);
}
int ans = 0;
fo(i, 1, n) add(ans, f[i]);
cout << ans;
}
