Problem:
Score : 100 points

Problem Statement

A string of length 6 consisting of lowercase English letters is said to be coffee-like if and only if its 3-rd and 4-th characters are equal and its 5-th and 6-th characters are also equal.

Given a string S, determine whether it is coffee-like.

Constraints

S is a string of length 6 consisting of lowercase English letters.

Input

Input is given from Standard Input in the following format:

S

Output

If S is coffee-like, print Yes; otherwise, print No.

Sample Input 1

sippuu

Sample Output 1

Yes

In sippuu, the 3-rd and 4-th characters are equal, and the 5-th and 6-th characters are also equal.

Sample Input 2

iphone

Sample Output 2

No

Sample Input 3

coffee

Sample Output 3

Yes

Solution in PHP7 (7.0.15) (judge verdict: Accepted)

<?php

    $s = in();
    if (substr($s, 2, 1) == substr($s, 3, 1) && substr($s, 4, 1) == substr($s, 5, 1)) {
        Yes();
    } else {
        No();
    }
    
    
    /**
    * お手伝い関数さんたち
    */
    function in() {
        return trim(fgets(STDIN));
    }
    function in_int() {
        return (int)in();
    }
    function in_vals() {
        return explode(' ', in());
    }
    function in_ints() {
        return array_map('intval', in_vals());
    }
    function out($s) {
        echo $s . PHP_EOL;
    }
    function yes() {
        out('Yes');
    }
    function no() {
        out('No');
    }
    function factorial($n) { // 階乗
        if ($n > 0) {
            return $n *= factorial($n - 1);
        }
        return 1;
    }
    function is_palindrome($s) {  // 回文か
        return $s == strrev($s);
    }