#include<bits/stdc++.h>

using namespace std;

int main() {
	int i, k, s;
	scanf("%d%d%d", &i, &k, &s);
	
	int ai, bi;
	scanf("%d%d", &ai, &bi);
	
	double a = ai, b = bi;
	if ((i&1) != (k&1)) {
		i++;
		a = sqrt(2.0) * ((ai + bi) - sqrt(3.0) * (ai - bi));
		b = sqrt(2.0) * ((ai - bi) + sqrt(3.0) * (ai + bi));
	}
	double ans = (a + b) * pow(2.0, 2*(k-i) - s);
	printf("%.10f\n", ans);
}