> #include<iostream.h>
> #include<math.h>
> 
> int main()
> {
> 	int n1,n2,n0,r;
> 	int i;
> 	
> 	while(cin>>n1>>n2>>n0>>r)
> 	{
> 		if(n1==0&&n2==0&&n0==0&&r==0)
> 		{
> 			break;
> 		}
> 		int day1=0,day2=0,day0=0;
> 		int c[110]={0};
> 		for(i=0;i<=ceil(100/(r+2));i++)
> 		{
> 			day0=n0*ceil(100/r);
> 			day1=n1*(i+ceil((100-i*(r+2))/r));
> 			day2=n2*(i +ceil(ceil(100-i*(r-1))/r));
> 		/*	if(i==ceil(100/(r+2)))
> 			{
> 				cout<<day2<<"   " <<ceil(ceil(100-i*(r-1))/r)<<endl;
> 				cout<<i<<endl;
> 			}*/
> 			c[i]=day0+day1+day2;
> 		}
> 		int 	min=c[0];
> 
> 	/*	for(i=0;i<=ceil(100/(r+2));i++)
> 		{
> 			cout<<c[i]<<endl;
> 		}*/
> 		//cout<<endl;
> 		for(i=0;i<=ceil(100/(r+2));i++)
> 		{
> 			if(c[i]<min)
> 			{
> 				min=c[i];
> 			}
> 		}
> 		cout<<min<<endl;
> 	}
> 	return 0;
> }