For this Question: The students of Newton School threw a grand party to celebrate their hard work and achievements. They danced and sang the night away, enjoying delicious food and creating memories that would last a lifetime. 
There are N guests in the party and N-1 relationships are given. The guests are numbered 1, 2, N. The i<sub>th</sub> relationship depicts that guest a<sub>i</sub> and guest b<sub>i</sub> are friends.
Determine whether a guest exists or not who is a friend of all other guests.
Here, we only consider direct friendship.Input is given from Standard Input in the following format:
N
a1 b1
a2 b2
a3 b3
.
.

an-1 bn-1

<b>Constraints</b>
3 &le; N &le; 10<sup>5</sup>
1 &le; ai, bi &le; N
i&le;NIf a guest exists or who is a friend of all other guests, print "Yes" else print "No".<b>Sample Input 1</b>
5
1 4
2 4
3 4
4 5

<b>Sample Output 1</b>
Yes

<b>Sample Input 2</b>
4
2 4
1 4
2 3

<b>Sample Output 2</b>
No

<b>Sample Input 3</b>
10
3 10
4 10
9 10
1 10
7 10
5 10
2 10
8 10
6 10

<b>Sample Output 3</b>
Yes

<b>Explanation</b>
In the first case,4 is a friend of everyone else's, while in the third case, 10 is a friend to all, while there is no such number in the second case., I have written this Solution Code: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
signed main()
{
    ll n;
    cin >> n;
    vector<ll> guests(n + 1, 0); // Counts the number of friends of each guest
    for (ll i = 1; i <= n - 1; i++)
    {
        ll a, b;
        cin >> a >> b;
        guests[a]++;
        guests[b]++;
    }
    for (ll i = 1; i <= n; i++)
    {
        if (guests[i] == n - 1) // If any guest is friend with all other guests than we have to return YES
        {
            cout << "Yes" << endl;
            return 0;
        }
    }
    cout << "No" << endl;
    return 0;
}
, In this Programming Language: C++, Now tell me if this Code is compilable or not?