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 k = sc.nextInt();
		long lcm = getLCM(a, b);
		long left = 0;
		long right = Long.MAX_VALUE / 2;
		while (right - left > 1) {
		    long m = (left + right) / 2;
		    long count = m / a + m / b - m / lcm;
		    if (count >= k) {
		        right = m;
		    } else {
		        left = m;
		    }
		}
	    System.out.println(right);
	}
	
	static long getLCM(long a, long b) {
	    return a / getGCD(a, b) * b;
	}
	
	static long getGCD(long a, long b) {
	    if (a % b == 0) {
	        return b;
	    } else {
	        return getGCD(b, a % b);
	    }
	}
}