Big Yield

Time limit1sMemory limit1024 MB

Summary

Given the total milk L and the pouring time T, find the difference between the two buckets' amounts, where the longer pour equals the larger bucket.

Level: Easy2 of 10
Topics: Math, Implementation
Solved: No attempts yet

Statement

Archip and Bronislav advanced to the final of a milk-yield contest called Big Yield. In each round, every participant milked one bucket of milk (possibly not full), then the results were written on a sheet of paper, and the buckets were tipped into a large vat at the same time. A mark on the vat showed that the total was $L$ liters. Just as the participants were distracted by the prize ceremony, a goat ate the sheet of paper.

Baba Nadya, who recently got a hearing aid, said she could recover the results by ear. From long experience, she knows that milk flows out of a bucket at 1 liter per second. By listening, she determined that the milk was pouring for $T$ seconds during the final. Help answer the question: by how many liters did the winner outpace the loser?

Input

The first line contains an integer $L$ , the number of liters of milk the finalists milked in total ( $1 \le L \le 10^9$ ).

The second line contains an integer $T$ , the time during which the milk was pouring ( $1 \le T \le 10^9$ , $T \le L < 2 \cdot T$ ).

Output

Print a single integer: the difference between the amounts of milk, in liters, that the finalists milked.

Examples3

Example 1
Input
```
3
2
```
Expected output
```
1
```
Example 2
Input
```
6
4
```
Expected output
```
2
```
Example 3
Input
```
42
24
```
Expected output
```
6
```