#include <stdio.h>
#include <unistd.h>

void ft_ulstr(char str[])
{
    int i;
    i = 0;

    while (str[i])
        {
            if (str[i] >= "a" && str[i] <= "z")
                write(1, &str[i] - 32, 1);
            else if (str[i] >= "A" && str[i] <= "Z")
                write(1, &str[i] + 32, 1);
            else
                write(1, &str[i], 1);
            i++;
        }
}

int main() 
{
    if (ac == 2)
        ft_ulstr(av[1]);
        write (1, "\n", 1);
    else
        write (1, "\n", 1);
    return 0;
}