B'There are n cities numbered from 1 to n , and city i has beauty a_i . A salesman wants to start at city 1 , visit every city exactly once, and return to city 1 . For all i ne j , a flight from city i to city j costs max(c_i,a_j-a_i) dollars, where c_i is the price floor enforced by city i . Note that there is no absolute value. Find the minimum total cost for the salesman to complete his trip. The first line contains a single integer n ( 2 <= n <= 10^5 ) -- the number of cities. The i -th of the next n lines contains two integers a_i , c_i ( 0 <= a_i,c_i <= 10^9 ) -- the beauty and price floor of the i -th city. Output a single integer -- the minimum total cost. In the first test case, we can travel in order 1 to 3 to 2 to 1 . The total cost is 11 , and we cannot do better. '...