Given a list of advertisements for a building choose the ones which maximized the total income from the advertisements. Each advertisements spans the whole face of the building, so no two advertisements can occupy the same floor and no floors can be partially occupied.

Input starts with an integer N, denoting the total number of advertisements. Each advertisements is described using three integers, A ( 0 <= A <= 10 ^ 5 ) , B( 1 <= B <= 10 ^ 5 ) and C ( 1 <= C <= 1000 ) denoting the lowest floor of the advertisement, the number of floor the advertisement covers( including the lowest floor ) and the money earned from placing it, respectively.


Sample Input:
3
1 5 1
2 10 3
7 12 1

Ans : 3

how can this problem be solved ?