/*
	Author: Ritik Patel
*/
 
 
//&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& STL DEBUGGER &&&&&&&&&&&&&&&&&&&&&&&&&&&
 
// #define _GLIBCXX_DEBUG       // Iterator safety; out-of-bounds access for Containers, etc.
// #pragma GCC optimize "trapv" // abort() on (signed) integer overflow.
 
//&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& LIBRARIES &&&&&&&&&&&&&&&&&&&&&&&&&&&
 
#include <bits/stdc++.h>
using namespace std;
 
/*#include <ext/pb_ds/assoc_container.hpp> // Common file
#include <ext/pb_ds/tree_policy.hpp> // Including tree_order_statistics_node_update
template<typename T, typename V = __gnu_pbds::null_type>
using ordered_set = __gnu_pbds::tree<T, V, less<T>, __gnu_pbds::rb_tree_tag, __gnu_pbds::tree_order_statistics_node_update>; 
*/
//find_by_order()->returns an iterator to the k-th largest element(0-based indexing)
//order_of_key()->Number of items that are strictly smaller than our item
 
//&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& DEFINES &&&&&&&&&&&&&&&&&&&&&&&&&&&
 
#define int long long int
// #define ll long long int
#define all(i) i.begin(), i.end()
#define sz(a) (int)a.size()
 
// #define ld long double
// const ld PI  = 3.141592;
const int dx4[4] = {0, 1, 0, -1};
const int dy4[4] = {-1, 0, 1, 0};
const int dx8[8] = {-1, -1, -1, 0, 1, 1, 1, 0};
const int dy8[8] = {-1, 0, 1, 1, 1, 0, -1, -1};
 
//&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& DEBUG &&&&&&&&&&&&&&&&&&&&&&&&&&&
 
#define XOX
vector<string> vec_splitter(string s) {
    for(char& c: s) c = c == ','?  ' ': c;
    stringstream ss; ss << s;
    vector<string> res;
    for(string z; ss >> z; res.push_back(z));
    return res;
}
 
void debug_out(vector<string> __attribute__ ((unused)) args, __attribute__ ((unused)) int idx) { cerr << endl; }
template <typename Head, typename... Tail>
void debug_out(vector<string> args, int idx, Head H, Tail... T) {
    if(idx > 0) cerr << ", ";
    stringstream ss; ss << H;
    cerr << args[idx] << " = " << ss.str();
    debug_out(args, idx + 1, T...);
}
 
#ifdef XOX
#define debug(...) debug_out(vec_splitter(#__VA_ARGS__), 0, __VA_ARGS__)
#else
#define debug(...) 42
#endif
 
 
//&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& CODE &&&&&&&&&&&&&&&&&&&&&&&&&&&

struct data{
    int p, h;
    data() {}
    data(int _p, int _h): p(_p), h(_h) {}
};

vector<pair<int, pair<int, pair<int, int>> > > S;
bool vis[800005][2];
set<int> check;

int dfs(int i, int id, int which, int L, int R){
    
    vis[id][which] = true;

    int lo = i, hi = sz(S) - 1;
    while(lo < hi){
        int mid = (lo + hi) / 2;
        if(S[mid].first >= R){
            hi = mid;
        } else {
            lo = mid + 1;
        }
    }

    int ans = R - L; 
    for(int j = lo; j < sz(S); ++j){
        auto p = S[j];
        int start = p.first;
        int end = p.second.first;
        int ii = p.second.second.first;
        int whichii = p.second.second.second;
        if(start != R){
            break;
        }
        if(vis[ii][whichii] or check.count(ii)){
            continue;
        }
        check.insert(ii);
        ans = max(ans, dfs(j, ii, whichii, L, end));
        check.erase(ii);
    }
    return ans;
}

void solve(){

    int N; cin >> N;
    vector<data> A(N);

    //Reset
    S.clear();
    for(int i = 0; i <= N; ++i){
        for(int j = 0; j < 2; ++j){
            vis[i][j] = false;

        }
    }


    for(int i = 0; i < N; ++i){
        int x, y; cin >> x >> y;
        A[i] = {x, y};
        // debug(A[i].p, A[i].h);
    }
    
    for(int i = 0; i < N; ++i){
        S.push_back( { A[i].p - A[i].h, {A[i].p , {i, 0} } } );
        S.push_back( { A[i].p , {A[i].p + A[i].h, {i, 1} } } );
    }
    sort(all(S));

    int ans = 0;
    for(int i = 0; i < sz(S); ++i){

        auto p = S[i];
        int start = p.first;
        int end = p.second.first;
        int id = p.second.second.first;
        int which = p.second.second.second;
        // debug(i, start, end, id, which);

        if(vis[id][which]){
            continue;
        }
        check.clear();
        check.insert(id);
        ans = max(ans, dfs(i, id, which, start, end));
    }
    cout << ans << '\n';
    
}
 
int32_t main(){
    freopen("input.txt","r",stdin);
    freopen("output.txt","w",stdout); 
    ios_base::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);
    int T = 1; 
    cin >> T;
    for(int i = 1; i <= T; ++i){
        cout << "Case #" << i << ": ";
        solve();
    }
    return 0;
}
 
/*
Sample inp
*/