Maximum Order Volume
During the day, a supermarket will receive calls from customers who want to place orders. The supermarket manager knows in advance the number of calls that will be attempted, the start time, duration, and order volume for each call. Only one call can be in progress at any one time, and if a call is not answered, the caller will not call back. The manager must choose which calls to service in order to maximize order volume. Determine the maximum order volume.
Complete the function phoneCalls in the editor.
phoneCalls has the following parameter(s):
int start[n]: the start times of each callint duration[n]: the durations of each callint volume[n]: the volumes of each order
Returns
int: the maximum possible volume of orders that can be received
1Example 1

Constraints
Limits and guarantees your solution can rely on.
1 ≤ n ≤ 1051 ≤ start[i] ≤ 1091 ≤ duration[i] ≤ 1091 ≤ volume[i] ≤ 103