Shopping center

Candice wants to go to the mall to hang out with Jeremy. She looked at the bus schedule and found out that $n$ buses leave from their house in the direction of the shopping center today, $i$-th of them will stop near their house in $t_i$ minutes from the current moment and go from home to shopping center $l_i$ minutes. Help Candice determine the earliest time she can arrive at the mall.

Input

The first line contains one integer $n(1\le n\le 100)$ - the number of buses.

The next $n$ lines contain two integers $t_i$ and $l_i(1\le t_i,l_i\le 100)$ - the number of minutes that will pass before the $i$-th bus will pass Candice's house, and the number of minutes that the $i$-th bus will travel from the house to the mall.

Output

Print a single integer, the minimum number of minutes that Candace will need to arrive at the shopping center.

Examples