ref

package main
import (
    "bufio"
    "fmt"
    "os"
)
const eol = 13
var input *bufio.Reader
func cap(b byte) byte {
    if b >= 'a' {
        return b - 'a' + 'A'
    }
    return b
}
func dictate(t chan byte) {
    for {
        b, _ := input.ReadByte()
        t <- b
        if b == eol {
            break
        }
    }
}
func encrypt(t, c chan byte) {
    for {
        b := <-t
        if b == ' ' || b == '.' || b == eol {
            c <- b
        } else if cap(b) < 'X' {
            c <- b + 3
        } else {
            c <- b - 23
        }
    }
}
func send(c chan byte, d chan bool) {
    b := byte(0)
    for b != eol {
        b = <-c
        fmt.Print(string(b))
    }
    fmt.Println()
    d <- true
}


func main() {
    input = bufio.NewReader(os.Stdin)
    textchan := make(chan byte)
    cryptchan := make(chan byte)
    done := make(chan bool)
    go dictate(textchan)
    go encrypt(textchan, cryptchan)
    go send(cryptchan, done)
    <-done
}