Cover Points
Description
There are $n$ points on the plane, $(x_1,y_1), (x_2,y_2), \ldots, (x_n,y_n)$.
You need to place an isosceles triangle with two sides on the coordinate axis to cover all points (a point is covered if it lies inside the triangle or on the side of the triangle). Calculate the minimum length of the shorter side of the triangle.
First line contains one integer $n$ ($1 \leq n \leq 10^5$).
Each of the next $n$ lines contains two integers $x_i$ and $y_i$ ($1 \leq x_i,y_i \leq 10^9$).
Print the minimum length of the shorter side of the triangle. It can be proved that it's always an integer.
Input
First line contains one integer $n$ ($1 \leq n \leq 10^5$).
Each of the next $n$ lines contains two integers $x_i$ and $y_i$ ($1 \leq x_i,y_i \leq 10^9$).
Output
Print the minimum length of the shorter side of the triangle. It can be proved that it's always an integer.
Samples
3
1 1
1 2
2 1
3
4
1 1
1 2
2 1
2 2
4
Note
Illustration for the first example: 
Illustration for the second example: 