$S = input();
$str = '';
$arr_S = str_split($S);
for($i = 0; isset($arr_S[$i]); $i++):
    if(ctype_upper($arr_S[$i])): $str += strtolower($arr_S[$i]);
    elseif(ctype_lower($arr_S[$i])): $str += strtoupper($arr_S[$i]);
    else: $str += $arr_S[$i];
    endif;
endfor;
print $str;