How to run this Java code in IntelliJ?

package com.company;

public class Main {
    public static int main(String[] args) {
        public int diceRoll (int sides){
            //This expression generates a random double in the interval
            //[0, sides). That is, a double greate than or equal to 0
            //and less than sides.
            double randomNumber = Math.random() * sides;
            //Our random number is now in the interval [1, sides +1)
            randomNumber = (randomNumber + 1);
            //Casting the random number to an integer will round it down to an
            //integer in the 1 to sides range
            return (int) randomNumber;
        }

        /**
         * The function monopolyRoll will simulate two dice rolls,
         * It will then store the sum
         * Check to see if rollOne and rollTwo are equal
         * If so, roll again and add new sums to previous total
         * If not, simply return sum of the first two rolls
         */
        public int monopolyRoll () {
            int rollOne = diceRoll(6);
            int rollTwo = diceRoll(6);
            int total = rollOne + rollTwo;
            if (rollOne == rollTwo) {
                int rollThree = diceRoll(6);
                int rollFour = diceRoll(6);
                total = total + rollThree + rollFour;
            }
            return total;
        }
    }
}