const lines = require('fs')
  .readFileSync('/dev/stdin', 'utf-8')
  .trim().split('\n').values();

let S = lines.next().value;

S = [...S];

for (let i = 0; i < S.length; i++) {
  if (S[i].charCodeAt(0) < 'a') {
    S[i] = S[i].toLowerCase();
  } else {
    S[i] = S[i].toUpperCase();
  }
}

console.log(S.join(''));