Var
num: array[1..4] of integer;
min, max: integer;
begin
read(num[1], num[2], num[3], num[4]);
min := num[1];
max := num[1];
for var k := 1 to 4 do if num[k] >= max then max := num[k];
for var k := 1 to 4 do if num[k] <= min then min := num[k];<br>write(max - min);
end.