C++ :

#include<iostream>
using namespace std;
int main()
{
	string str;
	int c,s;
	while(getline(cin,str))
    {
        c=0;
        s=0;
		for(int i=0;i<str.size();i+=2)
		{
			switch (str[i])
			{
			case 'A':s+=4;break;
			case 'B':s+=3;break;
			case 'C':s+=2;break;
			case 'D':s+=1;break;
			case 'F':s+=0;break;
			default:c++;
			}
		}
		if(c>0)cout<<"Unknown"<<endl;
		else cout<<s<<endl;
    }
	return 0;
}