#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=0.2*a+0.1*b+0.2*c+0.5*d;
    printf("%.1f",sum);
    return 0;
}