You are given cubes of blue, yellow, and green colors. There are , , and cubes of each color respectively. All the cubes of each color are uniquely numbered with integers from to , , and (and thus, all the cubes are different from each other).
Let a set of cubes be interesting if it has at least two cubes, and all cubes in it have different colors.
Count the number of interesting sets you can construct using given cubes.
For example, if there is blue cube, yellow cubes, and green cube, there are interesting sets:
first
blue cube and first
yellow cube;
first
blue cube and second
yellow cube;
first
blue cube and first
green cube;
first
yellow cube and first
green cube;
second
yellow cube and first
green cube;
first
blue cube, first
yellow cube and first
green cube;
first
blue cube, second
yellow cube and first
green cube;
The first and only line contains three integers , , — the number of cubes of each color.
The first and only line should contain the number of interesting sets of cubes.
The first test was explained in the statement.
In the second test, there are only interesting sets of cubes:
first
yellow cube and first
green cube;
second
yellow cube and first
green cube.
( points): ;
( points): ; ;
( points): ;
( points): no additional constraints.