#include <stdio.h>
int main() {
    int a = 0, b = 0, c = 0, d = 0;
    float sum = 0;
    scanf("%d %d %d %d", &a, &b, &c, &d);
    sum = a * 0.2 + b * 0.1 + c * 0.2 + d * 0.5;
    printf("%.1f", sum);
    return 0;
}