#include <stdio.h>

int main() 
{
    int a,b,c,d;
    float score;
    scanf("%d %d %d %d",&a,&b,&c,&d);
    score = a*0.2+b*0.1+c*0.2+d*0.5;
    printf("%.1f",score);

    return 0;
}