#include <bits/stdc++.h>

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

int main() {
	int a = ri(), b = ri();
	int p = ri(), q = ri(), r = ri();
	printf("%f\n", b + ((double) (p * b - (b - a) * q) / (r + q)));
	return 0;
}


