#include<stdio.h>
int main()
{
  int x; price x;
  int y; price y;
  int z; price z;
  int totalcost=0;
  if(scanf("%d%d",&x,&price x)!=2||x<0||price<0)
  {
      printf("Invalid input");
  }
  else if(scanf("%d%d",&y,&price y)!=2||y<0||price y<0)
  {
      printf("Invalid input");
  }
  else if(scanf("%d%d",&z,&price z)!=2||z<0||price z<0)
  {
      printf("Invalid input");
  }
  totalcost=(x*price x)+(y*price y)+(z*price);
  {
      printf("%d",totalcost);
  }
    
}