hdu 4256 The Famous Clock

#include<stdio.h>
int main()
{
	int i,sum,t=1,b,a;
	char s[10];
	while(scanf("%s",s)!=-1)
	{
	    	sum=0;
		    if(s[0]=='I')
				b=1;
			else if(s[0]=='V')
				b=5;
			else if(s[0]=='X')
				b=10;
			sum+=b;
		for(i=1;s[i];i++)
		{
			if(s[i]=='I')
				a=1;
			else if(s[i]=='V')
				a=5;
			else if(s[i]=='X')
				a=10;
			if(a<=b)
				sum+=a;
			else
				sum+=(a-2*b);
		}
		printf("Case %d: %d\n",t++,sum);
	}
	return 0;
}