add 2 long int

 /*
                  ,     \    /      ,
                 / \    )\__/(     / \
                /   \  (_\  /_)   /   \
           ____/_____\__\@  @/___/_____\____
          |             |\../|              |
          |              \VV/               |
          |        ------___-------         |
          |__________Chuta Dragon___________|
           |    /\ /      \\       \ /\    |
           |  /   V        ))       V   \  |
           |/     `       //        '     \|
           `              V                '
        */
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
int main()
{
  int kase=1;
    int t;
    cin>>t;
    while(t--)
    {
  deque<int>q;
     int a;
    string str,btr,temp;

    cin>>str>>btr;
    int  s,b,i,j,sum=0,c=0,mod;

    if(btr.size()<str.size())swap(str,btr);
 s=str.size();
    b=btr.size();

 // cout<<" "<<str<<" "<<btr<<" ";
        j=s-1;
       for(i=b-1;i>=0;i--)
         {
             if(j>=0)
             {
                 a=btr[i]-48+str[j]-48;
                 sum=a+c;
                 // cout<<"\n"<<sum<<" ";

                 if(sum>9)c=1;
                 else c=0;
                 mod=sum%10;
              //   cout<<mod;
                 q.push_front(mod);

               j--;
              }
             else
             {
                 a=btr[i]-48+c;
                 mod=a%10;
                 q.push_front(mod);
                   if(a>9)c=1;
                 else c=0;
             }

         }


 if(c==1)q.push_front(1);


 cout<<"Case #"<<kase++<<": ";

    for(auto x:q)
    {
        cout<<x;
    }

 cout<<"\n";





}

}