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>
#include<string.h>

int main(){
    char str[6];
    scanf("%s", str);//input the string
    int i;
    int flag = 1;
    for(i = 0; i < 6; i++){
        if(str[i] >= 'a' && str[i] <= 'z'){
            continue;
        }else{
            flag = 0;
            break;
        }
    }
    if(flag == 1){
        if((str[0] == str[1]) || (str[0] == str[2]) || (str[0] == str[3]) || (str[0] == str[4]) || (str[0] == str[5])){
        printf("No\n");
        }else if((str[1] == str[2]) || (str[1] == str[3]) || (str[1] == str[4]) || (str[1] == str[5])){
              printf("No\n");
       }else if((str[2] == str[4]) || (str[2] == str[5])){
             printf("No\n");
       }else if((str[3] == str[4]) || (str[3] == str[5])){
             printf("No\n");
       }else if(str[2] == str[3] && str[4] == str[5]){
             printf("Yes\n");
       }else{
             printf("No\n");
       }
    }else{
        printf("No\n");
    }
    return 0;
}