#include <string.h>
char Upcase(char ch)
{
 if (ch>='a' && ch<='z') return(ch-32);
 else return(ch);
}

char GetChoice(char *ok)
{char ch;
 do ch=Upcase(getc(stdin)); while (strchr(ok,ch)==NULL);
 return(Upcase(ch));
}