package main

import (
    "fmt"
    "strings"
)

func rot13char(c rune) rune {
    if c >= 'a' && c <= 'm' || c >= 'A' && c <= 'M' {
        return c + 13
    } else if c >= 'n' && c <= 'z' || c >= 'N' && c <= 'Z' {
        return c - 13
    }
    return c
}

func rot13(s string) string {
    return strings.Map(rot13char, s)
}

func main() {
    fmt.Println(rot13("nowhere ABJURER"))
}