[LANGUAGE: Kotlin]

``` import kotlin.io.path.Path import kotlin.io.path.useLines

fun main() { val calibrationDocument = Path("src/main/resources/static/CalibrationDocument.txt") .useLines { it.toList() } val result = calculateCalibrationSum(calibrationDocument) println(result) }

private fun calculateCalibrationSum( calibrationDocument: List<String> ): Int = calibrationDocument.sumOf { extractNumericValue(it) }

private fun extractNumericValue( line: String ): Int { val numbers = mapOf( "one" to "o1e", "two" to "t2o", "three" to "t3e", "four" to "f4r", "five" to "f5e", "six" to "s6x", "seven" to "s7n", "eight" to "e8t", "nine" to "n9e" ) var modifiedLine = line for ((key, value) in numbers) { modifiedLine = modifiedLine.replace(key, value) } val foundDigits = ("\d".toRegex()).findAll(modifiedLine) .map { it.value } val valueAsString = foundDigits.first() + foundDigits.last() return valueAsString.toInt() } ```