LOJ 1207

#include <bits/stdc++.h>
using namespace std;

struct cmp {
    bool operator() (int a, int b) const {
        return a > b;
    }
};

int main(){
    #ifdef ERFANUL007
        clock_t tStart = clock();
        freopen("input.txt", "r", stdin);
        freopen("output.txt", "w", stdout);
    #endif

    int t, cs = 0;
    scanf("%d", &t);

    while(t--){
        printf("Case %d: ", ++cs);
        int n; scanf("%d", &n);
        vector< int > shuru[n*2+2];
        vector< int > sesh[n*2+2];
        for(int i=1; i<=n; i++){
            int l, r; scanf("%d %d", &l, &r);
            shuru[l].push_back(i);
            sesh[r].push_back(i);
        }
        bool show[n+2];
        memset(show, 0, sizeof(show));
        set< int, cmp> pq;
        for(int i=1; i<=2*n; i++){
            for(auto it : shuru[i]){
                pq.insert(it);
            }
            if(pq.size()){
                show[*pq.begin()] = 1;
            }
            for(auto it : sesh[i]){
                pq.erase(pq.find(it));
            }
        }
        int ans = 0;
        for(int i=1; i<=n; i++) if(show[i]) ans++;
        printf("%d\n", ans);
    }


    #ifdef ERFANUL007
        fprintf(stderr, "\n>>> Runtime : %.9f\n", (double) (clock() - tStart) / CLOCKS_PER_SEC);
    #endif
    return 0;
}