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 C (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<stdio.h>
int a[300]={0};
int main ()
{  char s[7];
    int ans=0;
   for(int i=1;i<=6;i++)
     {
	 scanf("%c",&s[i]);
	     if(a[s[i]]==0) 
	       ans++,a[s[i]]++;
      }
      if(s[3]==s[4]&&s[5]==s[6])
         printf("YES");
    else   printf("NO");
    return 0;
}