#include<bits/stdc++.h> using namespace std; long long l,r; long long ans=0; const int mod=1e9+7; int main(){ cin>>l>>r; l=l-1; long long z=3,k=1; long long l1=l; long long l2=0; while(l>=z){ l-=z; l2+=z; z+=2; k++; } z/=2; if(k%2==1){ for(int i=l2+1;i<=l1;i++){ if(i-l2<=z+1) ans-=i; else ans+=i; ans=(ans+mod)%mod; } } else{ for(int i=l2+1;i<=l1;i++){ if(i-l2<=z+1) ans+=i; else ans-=i; ans=(ans+mod)%mod; } } //cout<<ans<<" "; z=3,k=1; l1=r; l2=0; while(r>=z){ r-=z; l2+=z; z+=2; k++; } z/=2; if(k%2==1){ for(int i=l2+1;i<=l1;i++){ if(i-l2<=z+1) ans+=i; else ans-=i; ans=(ans+mod)%mod; } } else{ for(int i=l2+1;i<=l1;i++){ if(i-l2<=z+1) ans-=i; else ans+=i; ans=(ans+mod)%mod; } } cout<<ans<<endl; }