a = 10
b = 9
c = 10
if a > b > c:
print(a-b-1+b-c-1)
elif a > c > b:
print(a-c-1+c-b-1)
elif b > a > c:
print(b-a-1+a-c-1)
elif b > c > a:
print(b-c-1+c-a-1)
elif c > a > b:
print(c-a-1+a-b-1)
elif c > b > a:
print(c-b-1+b-a-1)
elif c == b == a:
print(0)
elif a == b > c:
print(b - c - 1)
elif a > b == c:
print(a - b - 1)
elif a == c and c > b:
print(c - b - 1)
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