import math
 
a, b, c = map(int, input().split())
ab_gcd = math.gcd(a, b)
gcd = math.gcd(ab_gcd, c)
 
num_a = ( a // gcd ) -1
num_b = ( b // gcd ) -1
num_c = ( c // gcd ) -1

print(int(num_a  + num_b + num_c))