import java.util.*;

public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int a = sc.nextInt();
		int b = sc.nextInt();
		int t = sc.nextInt();
		if (t % a == 0 || t % b == 0) {
		    System.out.println(t);
		    return;
		}
		int count = 0;
		int min = Integer.MAX_VALUE;
		while (count * b < t) {
            min = Math.min(min, (t - count * b + a - 1) / a * a + count * b);
            if (min == t) {
                System.out.println(t);
                return;
            }
            count++;
		}
		min = Math.min(min, (t + b - 1) / b * b);
		System.out.println(min);
	}
}