"use strict";

/**
 * Resolves problem.
 * @param  {string} input
 * @returns {string}
 */
var main = function(input) {
    const items = input.split("\n").slice(1);
    let dictionary = {};
    for (const item in items) {
        dictionary[item] = 1;
    };
    const keys = Object.keys(dictionary);
    return keys.length;
};

const output = main(require("fs").readFileSync("/dev/stdin", "utf8"));
console.log(output); // console.log outputs with trailing new line!
