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.util.Scanner;

public class Main {

    public static void main(String[] args) {

    	Main main=new Main();

    	main.run();

    }

    void run() {
    	Scanner sc=new Scanner(System.in);
    	int N=sc.nextInt();

    	long[][] data=new long[N][2];

    	for(int i=0;i<N;i++) {
    		data[i][0]=sc.nextLong();
    		data[i][1]=sc.nextLong();
    	}

    	int max=-1;
    	int indexMAX=-1;
    	Long min=data[0][1];
    	int indexMIN=0;

    	for(int i=0;i<N;i++) {

    		Long buf=data[i][1];


    		if(min>buf) {
    			min=buf;
    			indexMIN=i;
    		}
    	}

    	Long result=data[indexMIN][0]+min;

    	System.out.println(result);

    }

}

