fun main() {
    val n = readLine()!!.split(' ')[0].toInt()
    val array: Array<Array<Char>> = Array(n) { Array(5) { ' ' } }

    for (i in array.indices) {
        array[i][i] = 'a'
    }

    var j = 0
    for (i in array.size - 1 downTo 0) {
        array[i][j] = 'a'
        ++j
    }

    var j1 = 1
    var j2 = 1
    var j3 = 0
    var j4 = 1


    for (i in 0..(n - 1) / 2) {

        //выше главной диагонали
        for (i1 in 0..array.size - j1 - 1) {
            if (array[i1][j1] == 'a') {
                continue
            }
            val next = getChar(i1, j1, array)
            array[i1][j1] = next
            j1++
        }
        j1 = i + 1

        //ниже главной диагонали
            var k1 = 0
        for (i2 in j2..array.size - 1) {
            if (array[i2][i2 - j2] == 'a') {
                continue
            }
            val next = getChar(i2, i2 - 1, array)
            array[i2][i2 - j2] = next
        }
        j2++

        //выше побочной диагонали
        for (i3 in array.size - 2 downTo 0) {
            if (array[i3][j3] == 'a') {
                continue
            }
            val next = getChar(i3, j3, array)
            array[i3][j3] = next
            j3++
        }
        j3 = 0

        //ниже побочной диагонали
        for (i4 in array.size - i - 1 downTo i + 1) {
            if (array[i4][j4] == 'a') {
                continue
            }
            val next = getChar(i4, j4, array)
            array[i4][j4] = next
            j4++
        }
        j4 = i + 1
    }


    for (i in array.indices) {
        for (k in array[i].indices) {
            print(array[i][k])
        }
        println()
    }
}

fun getChar(i: Int, j: Int, array: Array<Array<Char>>): Char {
    val left = if (j - 1 >= 0 &&
        i < array.size &&
        i >= 0 &&
        j - 1 < array.size
    ) {
        if (array[i][j - 1].isLetter()) {
            array[i][j - 1]
        } else {
            null
        }
    } else {
        null
    }

    val right = if (j + 1 < array[i].size &&
        i < array.size &&
        i >= 0 &&
        j + 1 >= 0
    ) {
        if (array[i][j + 1].isLetter()) {
            array[i][j + 1]
        } else {
            null
        }
    } else {
        null
    }

    val bottom = if (i + 1 < array.size &&
        j < array.size &&
        i + 1 >= 0 &&
        j >= 0
    ) {
        if (array[i + 1][j].isLetter()) {
            array[i + 1][j]
        } else {
            null
        }
    } else {
        null
    }

    val top = if (i - 1 >= 0 &&
        i - 1 < array.size &&
        j < array.size &&
        j >= 0
    ) {
        if (array[i - 1][j].isLetter()) {
            array[i - 1][j]
        } else {
            null
        }
    } else {
        null
    }

    val res = getCharFromNeighbours(
        left = left,
        right = right,
        top = top,
        bottom = bottom
    )
    println("res = $res")
    return res

}

fun getCharFromNeighbours(left: Char?, right: Char?, top: Char?, bottom: Char?): Char {
    var minChar = left ?: 'z'
    right?.let {
        if (minChar > right && right >= 'a' && right <= 'z') {
            minChar = right
        }
    }
    top?.let {
        if (minChar > top && top >= 'a' && top <= 'z') {
            minChar = top
        }
    }
    bottom?.let {
        if (minChar > bottom && bottom >= 'a' && bottom <= 'z') {
            minChar = bottom
        }
    }

    return getNext(minChar)
}

fun getNext(char: Char): Char {
    return if (char == 'z') {
        'a'
    } else {
        (char.toInt() + 1).toChar()
    }
}