let content = '';
process.stdin.resume();
process.stdin.setEncoding('utf8');
process.stdin.on('data', buf => {
  content += buf;
});

process.stdin.on('end', () => {
  const chars = content
    .trim()
    .split('')
    .map(s => s.toLowerCase())
    .filter(isLowerCase)

  const count = chars.reduce((prev, cur) => {
    return Object.assign({}, prev, {
      [cur]: prev[cur] === undefined ? 1 : prev[cur] + 1
    });
  }, {});
  
  for (let i = 97; i <= 122; i++) {
    const char = String.fromCharCode(i);
    console.log(`${char} : ${count[char] || 0}`);
  }
});

const isLowerCase = charCode => charCode >= 'a' && charCode <= 'z';
