function Main(input) {
  let output = '';

  for (var i = 0; i < input.length; i++) {
    let char = input.charAt(i);
    judgeCase(char);
  }

  function judgeCase(char) {
    let lowerRegexp = new RegExp(/[a-z]/, 'g');
    if (char.match(lowerRegexp)) {
      char = char.toUpperCase();
    } else {
      char = char.toLowerCase();
    }
    output += char;
  }

  console.log(output);
}
Main(require('fs').readFileSync('/dev/stdin', 'utf8'));