#include<stdio.h>
int main()
{
	long long int a, b, n, m;
	scanf("%lld %lld %lld %lld", &a, &b, &n, &m);
	if (a < b)
		printf("%lld\n", a + (b - a) / (m + 1));
	else
		printf("%lld\n", b + (a - b) / (n + 1));
	return 0;
}