#!/usr/bin/python3 from fractions import Fraction a, b, c = map(int, input().split()) assert -10**5 <= a <= 10**5 assert -10**5 <= b <= 10**5 assert -10**5 <= c <= 10**5 assert a != b r = Fraction(c-b, b-a) #import sys #print(r, file=sys.stderr) assert r != 0 d1 = b - r * a d2 = c - r * b assert d1 == d2 res = r * c + d1 print(res)