def main():
    A, B, C = map(int, input().split())
    money = 0
    age = 0
    while money < C:
        age += A
        money += B + (A - 1) * 1
    
    if money == C:
        print(age)
    else:
        money -= B
        age -= 1
        age -= money - C
        print(age)


if __name__ == "__main__":
    main()