#include <iostream>
#include <cstdio>
#include <vector>
#include <iterator>
#include <algorithm>
#include <utility>
#include <limits>

static const int r_size = 1000001;

//static int river[r_size] = {};

int main(){
     
    int N;
    std::scanf("%d", &N);
    
    for (int n = 0; n < N; ++n){
        std::vector<int> river(r_size, std::numeric_limits<int>::max());
        int height;
        int optimum = std::numeric_limits<int>::max();
        std::scanf("%d", &height);

        for (int h = 0; h < height; ++h){
            int left, right;
            std::scanf("%d %d", &left, &right);
            
            river[left] = 1;
           
            for (int i=left+1; i < right; ++i) {
                river[i] = std::min(river[i-1], river[i]) + 1;
//                std::printf("river %d is at %d", );
            }
            
            if (river[right - 1] < optimum) {
                optimum = river[right - 1];
            }
//            std::printf("Optimum is %d for height: %d\n", optimum, h);
        }
        
        printf("K prechodu reky je treba %d pontonu.\n", optimum);
        
    }

    return 0;
}