package MinimizingLateness;

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

public class MinimizingLateness {

  private static class Schedule { // Schedule class
    int t = 0; // Time required for the operation to be performed
    int d = 0; // Time the job should be completed
    int s = 0; // Start time of the task
    int f = 0; // End time of the operation

    public Schedule(int t, int d) {
      this.t = t;
      this.d = d;
    }
  }

  public static void main(String[] args) throws IOException {
    StringTokenizer token;

    BufferedReader in = new BufferedReader(new FileReader("MinimizingLateness/lateness_data.txt"));
    String ch = in.readLine();
    if (ch == null || ch.isEmpty()) {
      in.close();
      return;
    }
    int indexCount = Integer.parseInt(ch);
    System.out.println("Input Data : ");
    System.out.println(indexCount); // number of operations
    Schedule[] array = new Schedule[indexCount]; // Create an array to hold the operation
    int i = 0;
    while ((ch = in.readLine()) != null) {
      token = new StringTokenizer(ch, " ");
      // Include the time required for the operation to be performed in the array and the time it
      // should be completed.
      array[i] =
          new Schedule(Integer.parseInt(token.nextToken()), Integer.parseInt(token.nextToken()));
      i++;
      System.out.println(array[i - 1].t + " " + array[i - 1].d);
    }

    int tryTime = 0; // Total time worked
    int lateness = 0; // Lateness
    for (int j = 0; j < indexCount - 1; j++) {
      array[j].s = tryTime; // Start time of the task
      array[j].f = tryTime + array[j].t; // Time finished
      tryTime = tryTime + array[j].t; // Add total work time
      // Lateness
      lateness = lateness + Math.max(0, tryTime - array[j].d);
    }
    System.out.println();
    System.out.println("Output Data : ");
    System.out.println(lateness);
    in.close();
  }
}