Problem:
Score : 200 points

Problem Statement

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.

Sample Input 1

3
4 7
2 9
6 2

Sample Output 1

8

The maximum possible number of players is achieved when, for example, the players have the following scores: 12,9,8,7,5,2,1,0.

Sample Input 2

5
1 10
3 6
5 2
4 4
2 8

Sample Output 2

7

Sample Input 3

2
1 1000000000
1000000000 1

Sample Output 3

1000000001

Solution in C (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>
#include <stdlib.h>


int main(void)
{
    int i, n, *a, *b;
    int max = 0, min = 32767;
    int max_i = 0, min_i = 0;
    int ans = 0;
    scanf("%d", &n);
    getchar();
    a = (int *)malloc(sizeof(int)*n);
    b = (int *)malloc(sizeof(int)*n);

    for(i = 0; i < n; i++){
        scanf("%d %d", &a[i], &b[i]);
        getchar();
        if(b[i] > max){
            max = b[i];
            max_i = i;
        }
        if(b[i] < min){
            min = b[i];
            min_i = i;
        }
    }

    ans = a[min_i] - a[max_i];
    ans += a[max_i];
    ans += min;

    printf("%d\n", ans);

    return 0;
}