// #pragma GCC optimize("O3,unroll-loops")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#include <bits/stdc++.h>
#define ll long long
#define For(i,a,b) for(ll i=(a);i<=(b);i++)
#define Ford(i,a,b) for(ll i=(a);i>=(b);i--)
#define pb push_back
#define all(x) x.begin(), x.end()
#define fi first
#define se second
#define endl "\n"
using namespace std;
int Dx[] = {0, 1, 0, -1, -1, -1, 1, 1};
int Dy[] = {-1, 0, 1, 0, 1, -1, 1, -1};
int dx[] = {0, 1, 0, -1};
int dy[] = {-1, 0, 1, 0};
const ll inf = 1000000000000000000;
const int N = 100000;
const int block_size = 300;
const ll MOD = 1e9 + 7; /* 998244353 */
const int LG = 18;
const int K = 20;
const int M = 100000;
ll nph(ll k, ll x) { return ((x >> k) & 1LL); }
ll n,d[N+3],x[N+3],st[4*N], dp[N+3];
void update(ll idx, ll l, ll r, ll x) {
if(l > x || r < x) return;
if(l == r) {
st[idx] = dp[x];
return;
}
ll md = l + r >> 1;
update(2*idx, l, md, x);
update(2*idx+1, md+1, r, x);
st[idx] = st[2*idx] + st[2*idx+1];
}
ll get(ll idx, ll l, ll r, ll u, ll v) {
if(l > v || r < u) return 0;
if(u <= l && r <= v) return st[idx];
ll md = l + r >> 1;
return get(2*idx, l, md, u, v) + get(2*idx+1, md+1, r, u, v);
}
void Solve() {
cin>>n;
For(i, 1, n) cin>>d[i]>>x[i];
bool sub3 = true;
For(i, 1, n) if(d[i] != 1) sub3 = false;
if(n <= 1000) {
ll dp[n+3];
Ford(i, n, 1) {
//if(d[i] == 0) { dp[i] = 0; continue; }
dp[i] = 1;
if(d[i] == 0) continue;
ll j = 1;
while(i + j*d[i] <= n && j <= x[i]) {
dp[i] += dp[i+j*d[i]];
dp[i] %= MOD;
j++;
}
}
cout << dp[1]; return;
}
// if(sub3) {
// Ford(i, n, 1) {
// dp[i] = 1;
// if(d[i] == 0) {update(1, 1, n, i); continue;}
// if(i+1 <= min(n, i+x[i])) dp[i] += get(1, 1, n, i+1, min(n, i+x[i]));
// dp[i] %= MOD;
// update(1, 1, n, i);
// }
// cout << dp[1];
// }
}
int main() {
// freopen("PHOTO.INP", "r", stdin);
// freopen("PHOTO.OUT", "w", stdout);
ios_base::sync_with_stdio(0);
cin.tie(NULL);
cout.tie(NULL);
int t = 1;
//cin >> t;
while(t--)
Solve();
}
