#![allow(non_snake_case)]

use std::io::{ self, prelude::* };

macro_rules! pick {
    ($tokens:expr) => {
        $tokens.next().unwrap().parse().expect("parse error")
    }
}

fn f(A: u128, B: u128, x: u128) -> u128 {
    let k = x/A;
    B*k + x-k
}

fn main() {
    let mut s = String::new();
    io::stdin().read_to_string(&mut s).expect("i/o error");
    let mut tokens = s.split_whitespace();

    let A: u128 = pick!(tokens);
    let B: u128 = pick!(tokens);
    let C: u128 = pick!(tokens);

    let mut lo = 0;
    let mut hi = 1_000_000_000_000_000_000;
    while hi - lo > 1 {
        let mid = (lo+hi) / 2;
        if f(A,B,mid) < C {
            lo = mid;
        }
        else {
            hi = mid;
        }
    }

    let ans = hi;

    println!("{}", ans);
}