import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner stdin = new Scanner(System.in);
        long a = stdin.nextLong();
        long b = stdin.nextLong();
        long c = stdin.nextLong();
        
        long left = -1;
        long right = c + 1;
        while (right - left > 1) {
            long mid = left + (right - left) / 2;
            
            long sum = b * (mid / a) + (mid - mid / a);
            if (c <= sum) {
                right = mid;
            } else {
                left = mid;
            }
        }
        
        System.out.println(right);
    }
}