package main

import (
	"fmt"
)

func main() {
	var s string
	fmt.Scan(&s)
	for _, r := range s {
		if r <= 'Z' {
			r += 'a' - 'A'
		} else {
			r -= 'a' - 'A'
		}
		fmt.Printf("%c", r)
	}
	fmt.Println()
}