Problem:
Score : 300 points

Problem Statement

Find the price of a product before tax such that, when the consumption tax rate is 8 percent and 10 percent, the amount of consumption tax levied on it is A yen and B yen, respectively. (Yen is the currency of Japan.)

Here, the price before tax must be a positive integer, and the amount of consumption tax is rounded down to the nearest integer.

If multiple prices satisfy the condition, print the lowest such price; if no price satisfies the condition, print -1.

Constraints

1 \leq A \leq B \leq 100

A and B are integers.

Input

Input is given from Standard Input in the following format:

A B

Output

If there is a price that satisfies the condition, print an integer representing the lowest such price; otherwise, print -1.

Sample Input 1

2 2

Sample Output 1

25

If the price of a product before tax is 25 yen, the amount of consumption tax levied on it is:

When the consumption tax rate is 8 percent: \lfloor 25 \times 0.08 \rfloor = \lfloor 2 \rfloor = 2 yen.

When the consumption tax rate is 10 percent: \lfloor 25 \times 0.1 \rfloor = \lfloor 2.5 \rfloor = 2 yen.

Thus, the price of 25 yen satisfies the condition. There are other possible prices, such as 26 yen, but print the minimum such price, 25.

Sample Input 2

8 10

Sample Output 2

100

If the price of a product before tax is 100 yen, the amount of consumption tax levied on it is:

When the consumption tax rate is 8 percent: \lfloor 100 \times 0.08 \rfloor = 8 yen.

When the consumption tax rate is 10 percent: \lfloor 100 \times 0.1 \rfloor = 10 yen.

Sample Input 3

19 99

Sample Output 3

-1

There is no price before tax satisfying this condition, so print -1.

Solution in C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

/*BY-ADITYA OJHA
  LEARN DSA SINCERELY*/
#include <bits/stdc++.h>
#define ll long long int
#define forin for(int i=0;i<n;i++)
#define forjn for(int j=0;j<n;j++)
#define pb push_back
#define vx vector<ll> x
#define fas1  ios_base::sync_with_stdio(false)
#define fas2   cin.tie(NULL)
using namespace std;


int main()
{
     fas1;
     fas2;
      ll a,b;
      cin>>a>>b;
  ll i=0;
  ll z=max((a*100)/8,(b*10));
      if((a*100)/8<=z && z<=((a+1)*100)/8 && (b*10)<=z && z<=(b+1)*10 )
        {cout<<z<<endl;
        }

      else
        cout<<-1<<endl;


     return 0;

}