#include <bits/stdc++.h>
using namespace std;
#define ar array
#define int long long
#define ld long double
#define crash assert(69 == 420)
const int MOD = 1e9 + 7;
const int INF = 1e9;
const int N = 1e5 + 20;
const int K = 300;
const int LOG = 20;
int n;
int dp[N];
int ans;
int sum[K][N];
void upd(int i,int x){
for(int j = 0;j < K;j++){
sum[j][i] = x;
if(i + j < n)sum[j][i] += sum[j][i + j], sum[j][i] %= MOD;
}
}
signed main(){ios_base::sync_with_stdio(false);cin.tie(0);
cin>>n;
int d[n], t[n];
for(int i = 0;i < n;i++)cin>>d[i]>>t[i];
for(int i = n - 1;i >= 0;i--){
dp[i] = 1;
if(d[i] == 0){
upd(i, dp[i]);
continue;
}
if(d[i] >= K){
for(int j = 1;j <= t[i] && i + j * d[i] < n;j++)dp[i] += dp[i + j * d[i]], dp[i] %= MOD;
}else{
int l = i + d[i], r = i + (t[i] + 1) * d[i];
if(l < n)dp[i] += sum[d[i]][l];
if(r < n)dp[i] -= sum[d[i]][r];
dp[i] = (dp[i] % MOD + MOD) % MOD;
}
upd(i, dp[i]);
}
// for(int i = 0;i <n;i++)cout<<dp[i]<<" ";
//cout<<'\n';
cout<<dp[0];
}
