A group of people played a game. All players had distinct scores, which are positive integers.

Takahashi knows N facts on the players' scores. The i-th fact is as follows: the A_i-th highest score among the players is B_i.

Find the maximum possible number of players in the game.

Constraints

* 1 \leq N \leq 10^5
* 1 \leq A_i \leq 10^9(1\leq i\leq N)
* 0 \leq B_i \leq 10^9(1\leq i\leq N)
* If i ≠ j, A_i ≠ A_j.
* There exists a possible outcome of the game that are consistent with the facts.
* All input values are integers.

Inputs

Input is given from Standard Input in the following format:


N
A_1 B_1
:
A_N B_N


Outputs

Print the maximum possible number of players in the game.

Examples

Input

3
4 7
2 9
6 2


Output

8


Input

5
1 10
3 6
5 2
4 4
2 8


Output

7


Input

2
1 1000000000
1000000000 1


Output

1000000001
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {

  public static void main(String[] args) {
    new Main().run();
  }

  public void run() {

    try(BufferedReader in = new BufferedReader(new InputStreamReader(System.in))) {

      int n = Integer.parseInt(in.readLine());

      String[] lines;
      int maxK=0,maxV=0;
      int a,b;
      for(int i=0; i<n; i++) {
        lines = in.readLine().split(" ");
        a = Integer.parseInt(lines[0]);
        b = Integer.parseInt(lines[1]);
        if(a > maxK) {
          maxK = a;
          maxV = b;
        }
      }

      int ans = maxK + maxV;

      System.out.println(ans);
    }
    catch(IOException e) {
      System.err.println(e);
    }
  }
}