Three Kangaroos

Time limit1sMemory limit128 MB

Summary

Given three sorted integer positions, compute the maximum number of jumps where an outer point can move to any free integer strictly between the other two.

Level: Medium4 of 10
Topics: Math, Greedy, Simulation
Solved: No attempts yet

Problem

Three kangaroos are playing on an integer number line in the desert. They start on three distinct coordinates.

In one move, choose either the leftmost kangaroo or the rightmost kangaroo and make it jump to an empty integer coordinate strictly between the other two kangaroos. Two or more kangaroos may not occupy the same coordinate.

Find the maximum number of moves the kangaroos can make.

Input

The first line contains the initial positions A, B, and C of the three kangaroos, separated by spaces.

0 < A < B < C < 100

Output

Print the maximum number of moves the kangaroos can make.

Examples2

Example 1
Input
```
2 3 5
```
Expected output
```
1
```
Example 2
Input
```
3 5 9
```
Expected output
```
3
```