import kotlin.math.absoluteValue

fun main() {
    readInt()
    val a = readln()
    val b = readln()

    println(a.zip(b).sumOf {(x, y) ->
        val d = (x.code - y.code).absoluteValue
        minOf(d, 26 - d)
    })
}

private fun readInt() = readln().toInt()
private fun readLongs() = readStrings().map { it.toLong() }
private fun readStrings() = readln().split(" ")
private fun readInts() = readStrings().map { it.toInt() }