#include <bits/stdc++.h>
using namespace std;
#define int long long
#define ld long double
#define show(x,y) cout << y << " " << #x << endl;
#define show2(x,y,i,j) cout << y << " " << #x << " " << j << " " << #i << endl;
#define show3(x,y,i,j,p,q) cout << y << " " << #x << " " << j << " " << #i << " " << q << " " << #p << endl;
#define show4(x,y) for(auto it:y) cout << it << " "; cout << #x << endl;
typedef pair<int,int>pii;
typedef pair<int,pii>pi2;
const int blk=300;
const int mod=1e9+7;
void solve(){
int n;
cin >> n;
int temp,temp2;
vector<int>adj[n+5];
int cnt[305][305];
memset(cnt,0,sizeof(cnt));
vector<int>prefix[n+5];
vector<int>done[n+5];
int arr[n+5];
for(int x=1;x<=n;x++){
cin >> temp >> temp2;
arr[x]=temp;
if(temp==0) continue;
if(temp>=blk){
for(int y=x+temp;y<=n;y+=temp){
if(temp2==0) break;
temp2--;
adj[x].push_back(y);
}
}
else{
int hold=(n-x)/temp;
temp2=min(temp2,hold);
prefix[x].push_back(temp);
prefix[x+temp2*temp].push_back(-x);
}
}
int dp[n+5];
memset(dp,0,sizeof(dp));
dp[1]=1;
for(int x=1;x<=n;x++){
//show(x,x);
for(int y=1;y<blk;y++){
dp[x]=(dp[x]+cnt[x%y][y]+mod)%mod;
}
for(auto it:adj[x]){
dp[it]=(dp[it]+dp[x])%mod;
}
for(auto it:prefix[x]){
if(it>0){
//show(it,it);
cnt[x%it][it]+=dp[x];
cnt[x%it][it]%=mod;
}
else{
int hold=-it;
//show(hold,hold);
cnt[hold%arr[hold]][arr[hold]]-=dp[hold]-mod;
cnt[hold%arr[hold]][arr[hold]]%=mod;
}
}
//show4(dp,dp);
}
//show4(dp,dp);
int counter=0;
for(int x=1;x<=n;x++){
counter=(counter+dp[x])%mod;
}
cout << counter;
}
int32_t main(){
ios::sync_with_stdio(0);
cin.tie(0);
int t=1;
//cin >> t;
//freopen("in.txt","r",stdin);
while(t--){
solve();
}
}
