#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define vi vector<ll>
#define vvi vector<vi>
#define pp pair<ll, ll>
#define vp vector<pp>
#define vvp vector<vp>
#define inf 1000000000
#define mod 1000000007
int main(){
cin.tie(0);
ios_base::sync_with_stdio(false);
ll n;
cin >> n;
vp A(n);
for(int i = 0; i < n; i++){
cin >> A[i].first >> A[i].second;
}
ll k = 200;
ll ANS = 0;
vi ans(n, 0);
ans[0] = 1;
//vvi B(k, vi(n, 0));
//vvi trash(k, vi(n, 0));
vvp discard(n + 2);
vector<vi> B(k);
for(int i = 1; i < k; i++){
B[i].resize(i + 1, 0);
}
for(int i = 0; i < n; i++){
ll real = ans[i];
for(int j = 1; j < B.size(); j++){
ll block = i % j;
real += B[j][block];
real %= mod;
}
ANS += real;
ANS %= mod;
if(A[i].first == 0){
for(pp trash : discard[i]){
B[trash.first][i % trash.first] -= trash.second;
B[trash.first][i % trash.first] %= mod;
}
continue;
}
if(A[i].first >= k){
for(int j = 1; j <= A[i].second; j++){
ll pos = i + j * A[i].first;
if(pos >= n) break;
ans[pos] += real;
ans[pos] %= mod;
}
}else{
ll block = i % A[i].first;
ll where = i / A[i].first;
ll pos = block * A[i].first + where;
B[A[i].first][block] += real;
B[A[i].first][block] %= mod;
discard[min((ll)discard.size() - 1, i + A[i].first * A[i].second)].push_back({A[i].first, real});
}
for(pp trash : discard[i]){
B[trash.first][i % trash.first] -= trash.second;
B[trash.first][i % trash.first] %= mod;
}
}
ANS %= mod;
ANS += mod;
ANS %= mod;
cout << ANS << '\n';
}
