public static void main(String[] args) {

    char[] array = new char[20]; // our array
    Scanner sc = new Scanner(System.in);

    for (int i = 0; i < 20; i++)
    {
        array[i] = sc.next().charAt(0); // scanning input from the user
    }

    System.out.println(mostCommon(array)); // printing the most common character

    sc.close();

}

// this function gets the array and returns the most common character
public static char mostCommon(char[] array)
{
    int max = -1; // will hold the max number of occurences
    int index = -1; // will hold the index of the most common character

    // we go through the array and find the number of occurences for each item.
    // we compare it to max and update it every time (if needed). also we update the index.

    for (int i = 0; i < array.length; i++)
    {
        int current = countTimes(array, array[i]); // this variable holds the no. of occurences for the current item.
        if (current >= max) // if the current item is more common than the max
        {
            max = current; // we update the max to be the current value
            index = i; // and we update the index so we can know where is the most common item.
        }
    }
    // by the end of the loop, "index" will hold the index of the most common character. all we need to do is return it.
    return array[index]; // we return the most common character.
}

// this function gets an array and a character and returns the number of occurences of the char in the array.

public static int countTimes(char[] array, char c)
{
    int count = 0; // counter variable
    for (int i = 0; i < array.length; i++)
    {
        if (array[i] == c) // if the character appears
            count++; // increment the counter
    }

    return count; // return the number of times it appears.
}