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: Accepted)

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
 
int main(int argc, char** args)
{
    char str[30];
    unsigned long maxVal=0;
    unsigned long maxPos=0;
    unsigned long pos=0,val=0;
    unsigned long n=0;
    unsigned long result=0;
    memset(str,'\0',sizeof(str));
    
    fgets( str,sizeof(str), stdin);
    n=atol(str);
    
    for( int i=0; i<n; i++ )
    {
        fgets( str,sizeof(str), stdin);
        pos=atol(strtok(str," "));
        val=atol(strtok(NULL," "));
        if( maxPos<pos )
        {
            maxPos=pos;
            maxVal=val;
        }
    }
    result=maxPos+maxVal;
    printf("%ld\n",result);
    fflush(stdout);
}