import kotlin.math.max

fun main() {
    val builder = StringBuilder()

    val n = readInputLine().toInt()

    val s = readInputLine()
    val t = readInputLine()

    var rowCnt = 0

    for (c in s) {
        when (c) {
            '1' -> rowCnt++
            '2' -> rowCnt += n
        }
    }

    var colCnt = 0

    for (c in t) {
        when (c) {
            '1' -> colCnt++
            '2' -> colCnt += n
        }
    }

    builder.appendln(max(rowCnt, colCnt))

    print(builder.toString())
}

fun readInputLine(): String {
    return readLine()!!
}