#include<bits/stdc++.h>
using namespace std;
long long r[10086],l[10086];
long long a;
int main(){
    int n;
    cin>>n;
    for(int i=1;i<=n;i++){
        cin>>l[i]>>r[i];
        a=(r[i]+l[i])*(r[i]-l[i]+1)/2; 
        cout<<a%9<<endl;
    }
	return 0;
}

@P4942