const main = require('fs').readFileSync('/dev/stdin','utf8').trim();
const array = main.split('');
const isUpperCase = c =>  /[A-Z]/g.test(c);
const isLowerCase = c =>  /[a-z]/g.test(c);
for (var i = 0; i < array.length; i++) {
    if (isUpperCase(array[i]) === true) {
        array[i] = array[i].toLowerCase();
    } else if (isLowerCase(array[i]) === true){
        array[i] = array[i].toUpperCase();
    }
}
const ans = array.join('');
console.log(ans);