#include <bits/stdc++.h>

int ri() {
	int n;
	scanf("%d", &n);
	return n;
}

int gcd(int a, int b) {
	while (a && b) {
		if (a > b) a %= b;
		else b %= a;
	}
	return a + b;
}

int main() {
	int a = ri();
	int b = ri();
	int k = ri();
	int64_t lcm = (int64_t) a / gcd(a, b) * b;
	
	int64_t l = 0;
	int64_t r = 1000000000000000000;
	while (r - l > 1) {
		int64_t m = l + ((r - l) >> 1);
		int64_t cnt = m / a + m / b - m / lcm;
		if (cnt >= k) r = m;
		else l = m;
	}
	printf("%" PRId64 "\n", r);
	
	return 0;
}