## A - Edge Checker Editorial by en_translator

The points numbered \(a\) and \(b\) are directly connected with a line segment if and only if \(b-a = 1\) or \(b-a = 9\).

Therefore, we can make the following program to get accepted for this problem.

- First, read \(a\) and \(b\) from the Standard Input.
- Next, check if \(b-a = 1\) or \(b-a=9\) holds.
- If it holds, output
`Yes`

to the Standard Output. - If it doesn’t, output
`No`

to the Standard Output.

- If it holds, output

Inputting and outputting can be achieved in different ways in different languages, so check the specification of the language you use.

In order to “check if \(b-a = 1\) or \(b-a=9\) holds,” you can use the conditional branch (like if statement), which is a standard feature of programming languages.

The following is a sample code in C++.

```
#include <iostream>
using namespace std;
int main(void)
{
int a, b;
cin >> a >> b;
if(b-a == 1 || b-a == 9) cout << "Yes" << endl;
else cout << "No" << endl;
return 0;
}
```

posted:

last update: