stock IsMail(email[]) {
  	new len=strlen(email), cstate=0, i;
  	for(i=0;i<len;i++) {
	    if((cstate==0 || cstate==1) && (email[i]>='A' && email[i]<='Z')||(email[i]>='0' && email[i]<='9') || (email[i]>='a' && email[i]<='z')  || (email[i]=='.')  || (email[i]=='-')  || (email[i]=='_')) { }
		else {
	       if((cstate==0) &&(email[i]=='@')) cstate=1;
		   else return false;
	 	}
	}
  	if(cstate<1) return false;
  	if(len<6) return false;
  	if((email[len-3]=='.') || (email[len-4]=='.') || (email[len-5]=='.')) return true;
  	return false;
}