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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <bits/stdc++.h>
#include <cstdio>
 
using namespace std;
using ll = long long;
 
#define rep(i, a) for (int i = 0; (i) < (int) (a); (i)++)
#define reps(i, a, b) for (int i = (int) (a); (i) < (int) (b); (i)++)
#define rrep(i, a) for (int i = (int) a-1; (i) >= 0; (i)--)
#define rreps(i, a, b) for (int i = (int) (a)-1; (i) >= (int) (b); (i)--)
#define MP(a, b) make_pair((a), (b))
#define PB(a) push_back((a))
#define all(v) (v).begin(), (v).end()
#define PERM(v) next_permutation(all(v))
#define UNIQUE(v) sort(all(v));(v).erase(unique(all(v)), v.end())
#define CIN(type, x) type x;cin >> x
#define TRUE__  "Yes"
#define FALSE__ "No"
#define PRINT(f) if((f)){cout << (TRUE__) << endl;}else{cout << FALSE__ << endl;}
#define RS resize
#define CINV(v, N) do {\
	v.RS(N);\
	rep(i, N) cin >> v[i];\
} while (0);
#define RCINV(v, N) do {\
	v.RS(N);\
	rrep(i, N) cin >> v[i];\
} while (0);
 
#define MOD 1000000007
void init();
void solve();

signed main()
{
    init();
    solve();
}

void init()
{
	int N;
	cin >> N;
	int res = INT_MAX;
	rep(i, N) {
		int a, b;
		cin >> a >> b;
		res = min(a+b, res);
	}
	cout << res << endl;
}

void solve()
{
}