contacts.js

process.stdin.resume();
process.stdin.setEncoding('ascii');

var input_stdin = "";
var input_stdin_array = "";
var input_currentline = 0;

process.stdin.on('data', function (data) {
    input_stdin += data;
});

process.stdin.on('end', function () {
    input_stdin_array = input_stdin.split("\n");
    main();    
});

function readLine() {
    return input_stdin_array[input_currentline++];
}

/////////////// ignore above this line ////////////////////

let recursiveCheck = (current) => {
  let numFound = 0
  for (let i in current) {
    let letter = current[i]
    if (i === '$') numFound++
    else numFound += recursiveCheck(letter)
  }
  return numFound
}
class Trie {
  constructor() {
    this.head = {}
  }
  add(word) {
    let current = this.head
    for (let i in word) {
      let letter = word[i]
      if (!current[letter]) current[letter] = {}

      current = current[letter]
    }
    current.$ = 1 //word end marker
  }
  numStartWith(word) {
    let current = this.head

    for (let i in word) {
      let letter = word[i]

      if (!(current[letter])) return 0
      current = current[letter]
    }

    return recursiveCheck(current)
  }
}


function main() {
    var n = parseInt(readLine());
    let trie = new Trie()
    for(var a0 = 0; a0 < n; a0++){
        var op_temp = readLine().split(' ');
        var op = op_temp[0];
        var contact = op_temp[1];
        if (op === 'add')
            trie.add(contact)
        if (op === 'find') {
            trie.numStartWith(contact)
            let count = trie.numStartWith(contact)
            console.log(count)
        }

    }

}