#include<bits/stdc++.h>
#define all(x) (x).begin() , (x).end()
#define pll pair<long long, long long>
#define pii pair<int , int>
#define fi first
#define se second
#define bit(i,j) ((j >> i) & 1)
using namespace std;
const long long inf = 1e18;
const int mod = 1e9+7;
const int MAXN = 2e5+100;
#define int long long
int mp[500][500];
int32_t main(){
//freopen("B.inp", "r", stdin);
//freopen("B.out", "w", stdout);
ios_base::sync_with_stdio(0); cin.tie(0);
int n; cin >> n;
vector<int> d(n+1) , x(n+1);
const int block = 320;
for(int i = 1 ; i <= n ; i++) cin >> d[i] >> x[i];
vector<int> dp(n+1);
dp[1] = 1;
priority_queue<pll , vector<pll> , greater<pll>> Q;
if(d[1] > block){
for(int i = 1 + d[1] ; i <= min(n , 1 + x[1] * d[1]) ; i += d[1]) dp[i] += 1;
}else if(d[1] != 0){
Q.push({1 + x[1] * d[1] , 1});
mp[d[1]][1%d[1]] += 1;
}
int ans = 1;
for(int i = 2 ; i <= n ; i++){
while(Q.size()){
pll t = Q.top();
if(t.fi < i){
if(d[t.se] != 0){
mp[d[t.se]][t.se%d[t.se]] = (mp[d[t.se]][t.se%d[t.se]] - dp[t.se] + mod) % mod;
}
Q.pop();
}
else break;
}
for(int j = 1 ; j <= block ; j++) dp[i] = (dp[i] + mp[j][i%j]) % mod;
ans = (ans + dp[i]) % mod;
if(d[i] == 0) continue;
if(d[i] > block){
for(int j = i + d[i] ; j <= min(n , i + x[i] * d[i]) ; j += d[i]) dp[j] = (dp[j] + dp[i]) % mod;
}else{
Q.push({i + x[i] * d[i] , i});
mp[d[i]][i%d[i]] += dp[i];
mp[d[i]][i%d[i]] %= mod;
}
}
cout << ans << "\n";
return 0;
}
