Problem p02723 (C++) — buggy submission, verdict: Runtime Error

/*
  _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
 |                                                                 |
 |   author : yash1399     Language : C ++                         |
 |   college : MSIT                                                |
 | _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ |
*/
#include <algorithm>
#include <bits/stdc++.h>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <functional>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
using namespace std;
#define ll long long int
#define TEST                                                                   \\
  int t;                                                                       \\
  cin >> t;                                                                    \\
  while (t--)
#define line cout << endl;
#define fast                                                                   \\
  ios_base::sync_with_stdio(false);                                            \\
  cin.tie(0);                                                                  \\
  cout.tie(0);
#define loop(i, a, b) for (long long int i = a; i < b; i++)
#define loopIn(i, a, b) for (long long int i = a; i <= b; i++)
#define Vi vector<int>
#define MAX_SIZE 1000000000
using namespace std;
int main() {
  fast string s;
  cin >> s;
  if (s[2] == s[3] && s[4] == s[5]) {
    cout << "Yes" << endl;
  } else {
    cout << "No" << endl;
  }

  return 0;
}


Error: WA

Fixed submission:

/*
  _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
 |                                                                 |
 |   author : yash1399     Language : C ++                         |
 |   college : MSIT                                                |
 | _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ |
*/
#include <algorithm>
#include <bits/stdc++.h>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <functional>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
using namespace std;
#define ll long long int
#define TEST                                                                   \\
  int t;                                                                       \\
  cin >> t;                                                                    \\
  while (t--)
#define line cout << endl;
#define fast                                                                   \\
  ios_base::sync_with_stdio(false);                                            \\
  cin.tie(0);                                                                  \\
  cout.tie(0);
#define loop(i, a, b) for (long long int i = a; i < b; i++)
#define loopIn(i, a, b) for (long long int i = a; i <= b; i++)
#define Vi vector<int>
#define MAX_SIZE 1000000000
using namespace std;
int main() {
#ifndef ONLINE_JUDGE
  freopen("input.txt", "r", stdin);
  freopen("output.txt", "w", stdout);
#endif
  fast string s;
  cin >> s;
  if (s[2] == s[3] && s[4] == s[5]) {
    cout << "Yes" << endl;
  } else {
    cout << "No" << endl;
  }

  return 0;
}