#include <bits/stdc++.h>
using namespace std;
#define int long long
#define speedIO ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define mod 1000000007
#define f first
#define s second
#define pii pair<int,int>
#define pb push_back
vector<vector<vector<int>>> bit;//step,start,value
const int block=100;
void update(int idx, int val, int step, int start){
while(idx<=bit[step][start].size()){
bit[step][start][idx]=(bit[step][start][idx]+val)%mod;
idx+=idx&(-idx);
}
}
int get(int idx, int step, int start){
int ans=0;
while(idx>0){
ans=(ans+bit[step][start][idx])%mod;
idx-=(idx)&(-idx);
}
return ans;
}
int32_t main(){
speedIO;
int t,n,m,k,q;
//cin>>t;
t=1;
while(t--){
cin>>n;
vector<int> d(n+1),x(n+1),dp(n+1,0);
bit.resize(block,vector<vector<int>>(block));
bit[1][1].resize(n+5,0);
for(int i=1;i<=n;i++){
cin>>d[i]>>x[i];
}
dp[1]=1;
//update(1,1,1);
for(int i=1;i<=n;i++){
dp[i]=(dp[i]+get(i,1,1));
if(d[i]==0) continue;
int l=i+1;
int r=min(n,i+x[i]);
if(l<=r){
update(l,dp[i],1,1);
if(r<n){
update(r+1,-dp[i],1,1);
}
}
}
/*cout<<'\n';
for(int i=0;i<=n+3;i++){
cout<<bit[1][1][i]<<' ';
}
cout<<'\n';
cout<<get(5,1,1)<<'\n';*/
int final=0;
for(int i=1;i<=n;i++){
final=(final+dp[i])%mod;
//cout<<dp[i]<<' ';
}
cout<<final<<'\n';
}
return 0;
}
