#include <stdio.h>
#include <ctype.h>

int main(void)
{
        int c;

        while ((c = getchar()) != EOF) {
                if (islower(c)) {
                        c = toupper(c);
                } else if (isupper(c)) {
                        c = tolower(c);
                }
                putchar(c);
        }

        return 0;
}