function main(input) {
  const args = input.split('\n');
  const N = parseInt(args[0], 10);
  let words = [];
  let ans = 'Yes';
  let pre_w;
  
  for (let i = 1; i < args.length; i++) {
    last_w = args[i].slice(args[i].length - 1);
    first_w = args[i].slice(0, 1);
    //初回
    if (!pre_w) {
      words.push(args[i]);
      pre_w = last_w;
    } else {
    //２回目以降
      if (pre_w === first_w) {
        if (!words.includes(args[i])) {
          words.push(args[i]);
          pre_w = last_w;
        } else {
          ans = 'No';
          break;
        }
      } else {
        ans = 'No';
        break;
      }
    }
  }
  console.log(ans);
}

main(require('fs').readFileSync('/dev/stdin', 'utf8'));