#!/usr/bin/env python
# -*- coding: utf-8 -*-

def solve():
    a, b, c = map(int, input().split())
    high, low = 10 ** 18, 1
    for _ in range(100):
        mid = (high + low) // 2
        money = b * (mid // a) + 1 * (mid - mid // a)
        if money < c:
            low = mid
        else:
            high = mid
    # print([low, mid, high])
    print(high)

if __name__=="__main__":
    solve()