Write a C$++$ program that allows user to enter the grades of N students $($N is determinedby the user$)$ and stores them into an array. Then the program should output the information below.Note$-$ Your program should be structured using functions. Each functionality should be implemented in aseparate function. In the main function, it takes the user input and call each of the user$-$defined functionsto do the calculation and print out the results in the main function$\mathrm{.}1-3$ highest grades, and the corresponding student indices$\mathrm{.}2-$ Median grade$\mathrm{.}3-$ Most frequently occurring grades. If multiple grades have the same highest frequency, list all ofthem$\mathrm{.}4-$ Grade distribution:$1)$ Number of A grades $($grades equal or more than $90)2)$ Number of B grades $($grades between $80($inclusive$)$ and $90)3)$ Number of C grades $($grades between $65($inclusive$)$ and $80)4)$ Number of D grades $($grades between $50($inclusive$)$ and $65)5)$ Number of F grades $($grades less than $50)*$Hint$-$ You should use std::vector to store the grades