wout.cpp

#include <iostream>
using namespace std;

int main() {
    int t;
    cin >> t;
    while(t--) {
        long int cave_size, tractor_size;
        cin >> cave_size >> tractor_size;
        int cave[cave_size][cave_size];
        long int col, row;
        for(col = 0; col < cave_size; col++) {
            long int I, H;
            cin >> I >> H;
            for(row = 0; row < cave_size; row++) {
                if(row < I || row > H) {
                    cave[col][row] = 1;
                } else {
                    cave[col][row] = 0;
                }
            }
        }
        for(row = 0;row < cave_size;row++) {
            for(col = 1; col < cave_size; col++) {
                cave[0][row] += cave[col][row];
            }
        }
        long long int energy, min_energy = cave_size * tractor_size;
        for(row = 0; row <= cave_size - tractor_size; row++) {
            energy = 0;
            for(col = 0; col < tractor_size; col++) {
                energy += cave[0][row + col];
            }
            if(energy < min_energy) {
                min_energy = energy;
            }
        }
        cout << min_energy << endl;
    }
  	return 0;
}