#include<bits/stdc++.h>
using namespace std;
#define int long long
int a,b,c,d,e,f[505],ans,mod=1e9+7;
vector<pair<int,int>>v;
map<int,int>ma,tema;
map<int,int>::iterator maa;
void cal(int x){
int temp=0;
maa=ma.begin();
for(int i=v[x].first;i<=v[x].second;i++){
while(maa->first<i and maa!=ma.end()){
temp+=maa->second;
temp=temp%mod;
maa++;
}
tema[i]+=temp;
tema[i]=tema[i]%mod;
}
for(maa=tema.begin();maa!=tema.end();maa++){
ma[maa->first]+=maa->second;
ma[maa->first]%=mod;
}
tema.clear();
}
signed main(){
ma[0]=1;
cin>>a;
for(int i=0;i<a;i++){
cin>>b>>c;
v.push_back({b,c});
}
for(int i=0;i<a;i++){
cal(i);
}
for(maa=ma.begin();maa!=ma.end();maa++){
ans+=maa->second;
ans=ans%mod;
}
cout<<ans-1;
}
