function main(input) {
  var marginDelete = input.trim().split("\n");
  var s = marginDelete;
  result = s.replace(/hi/g, "");
  if ( result.length == 0) {
    return "Yes";
  } else {
    return "No";
  }
}
console.log(main(require('fs').readFileSync('/dev/stdin', 'utf8')));