import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

/**
 *
 * @author durec4
 */
public class Most {
      StringTokenizer st = new StringTokenizer(" ");
      BufferedReader input = new BufferedReader(new InputStreamReader(System.in));
      boolean hasNextToken() throws IOException {
          while(!st.hasMoreTokens()){
              String line = input.readLine();
              if (line == null) return false;
              st = new StringTokenizer(line);
          }
          return true;
      }
      String nextToken() throws IOException {
          return (!hasNextToken())?null:st.nextToken();
      }
      static int[] a;
      static int[] b;
      public static void main(String[] args) throws Exception{
          Most instance = new Most();
          final int testCases = Integer.parseInt(instance.nextToken());
          for (int i = 0;i<testCases;i++){
              int height = new Integer(instance.nextToken());
              a = new int[height];
              b = new int[height];
              int minsize = 1000000;
              for (int j = 0;j<height;j++){
                  a[j] = new Integer(instance.nextToken());
                  b[j] = new Integer(instance.nextToken());
                  int vysledok = instance.riadok(j,minsize);
                  if (vysledok < minsize) minsize = vysledok;
                  
              }
              System.out.printf("K prechodu reky je treba %d pontonu.\n",minsize);
          }
      }
            
      int riadok(int poradie,int minsize){
          int limit;
          if (poradie < minsize) limit = poradie;
          else {
              limit = minsize;
          }
          for (int i = 0; i<=limit;i++){
              int dlzka = (b[poradie]-a[poradie-i]+i);
              if (dlzka<minsize) minsize = dlzka;
          }
          return minsize;
      }
}