#D11445. Apple Pie
Apple Pie
Apple Pie
We have A apples and P pieces of apple.
We can cut an apple into three pieces of apple, and make one apple pie by simmering two pieces of apple in a pan.
Find the maximum number of apple pies we can make with what we have now.
Constraints
- All values in input are integers.
- 0 \leq A, P \leq 100
Input
Input is given from Standard Input in the following format:
A P
Output
Print the maximum number of apple pies we can make with what we have.
Examples
Input
1 3
Output
3
Input
0 1
Output
0
Input
32 21
Output
58
inputFormat
input are integers.
- 0 \leq A, P \leq 100
Input
Input is given from Standard Input in the following format:
A P
outputFormat
Output
Print the maximum number of apple pies we can make with what we have.
Examples
Input
1 3
Output
3
Input
0 1
Output
0
Input
32 21
Output
58
样例
1 33