**A. Easy Problem?**

**Solution**

According to Euler's Formula -- *Faces + Vertices — Edges = 2*

**Solution Code**

```
#include <bits/stdc++.h>
using namespace std;
#define ll long long int
#define ff first
#define ss second
void solvr()
{
char a, b;
cin >> a >> b;
ll one, two;
cin >> one >> two;
bool f = false;
bool v = false;
bool e = false;
if(a == 'F')
{
f = true;
}
else if(a == 'V')
{
v = true;
}
else
{
e = true;
}
if(b == 'F')
{
f = true;
}
else if(b == 'V')
{
v = true;
}
else
{
e = true;
}
if(f && v)
{
cout << "E" << endl;
cout << one + two - 2 << endl;
}
else if(f && e)
{
cout << "V" << endl;
if(a == 'E')
{
cout << one + 2 - two << endl;
}
else
{
cout << two + 2 - one << endl;
}
}
else
{
cout << "F" << endl;
if(a == 'E')
{
cout << one + 2 - two << endl;
}
else
{
cout << two + 2 - one << endl;
}
}
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
long long int t = 1;
//cin >> t;
while(t--)
{
solvr();
}
}
```

**B. Polygon Is Irregular?**

**Solution**

n ==> (k-2)(180) / k [Interior angle formula for k-sided regular polygon] kn = 180k — 360 360 = k(180-n) 180-n should be divisible by 360, and k should be greater than 2

Be careful, n equal to 180 will give runtime error if not handled as division by zero is invalid.

**Solution Code**

```
#include <bits/stdc++.h>
using namespace std;
#define ll long long int
#define ff first
#define ss second
void solvr()
{
ll n;
cin >> n;
if((180-n) > 0 && 360 % (180-n) == 0 && (360 / (180-n)) > 2)
{
cout << "YES" << endl;
cout << 360 / (180-n) << endl;
}
else
{
cout << "NO" << endl;
}
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
long long int t = 1;
//cin >> t;
while(t--)
{
solvr();
}
}
```

Auto comment: topic has been updated by ishat_jha (previous revision, new revision, compare).pls add more questions next time.. only 2 problem isn't enough, I think..

It was my first time, was just testing a bit, from the next will create around 4-5 problems and then post the blog for the contest.

Euler's formula is too hard for beginners. All they can do with it is just use it's raw form. Problems that require it's application are all 2000 at least.

Also, you need to make your statements more clear. Edges/Faces/Vertices of what? And in second problem it is unclear what k is. The legend makes it seem like it's given, but it's integer you output.

Thanks for the feedback and sorry for the faults. This was my first time I set some problems without any one's help. I had the same suggestion from another master so will surely inculcate it in future contests.

I thought it's raw form could be good enough to make a 1000 rated problem.