import java.util.Stack;
import java.util.*;

class RPNLogic implements RPNLogicInterface{
	int fail=1;
	RPNLogic(){;};
	Stack<Boolean> one = new Stack<Boolean> ();
	public void truee(){
		if(fail==1){
			one.push(true);
			}
		}
	public void falsee(){
		if(fail==1){
			one.push(false);
			}
		}
	public void and(){
		if(fail==1){
			try{
				Boolean oine = one.pop();
				Boolean two = one.pop();
				one.push(oine&two);
			}catch(EmptyStackException e){
				clear();
				fail=0;
				}
			}
		}
	public void or(){
		if(fail==1){
			try{
				Boolean oine = one.pop();
				Boolean two = one.pop();
				one.push(oine||two);
			}catch(EmptyStackException e){
				clear();
				fail=0;
				}
			}
		}
	public void not(){
		if(fail==1){
			try{
				Boolean oine = one.pop();
				one.push(!(oine));
			}catch(EmptyStackException e){
				clear();
				fail=0;
				}
			}
		}
	public void vote3(){
		if(fail==1){
			try{
				Boolean oine = one.pop();
				Boolean two = one.pop();
				Boolean three = one.pop();
				if((oine&&two&&three==true)|((oine&&two)==true)|((oine&&three)==true)|((two&&three)==true)){
					one.push(true);
				}else{
					one.push(false);
				}
			}catch(EmptyStackException e){
				clear();
				fail=0;
			}
		}
	}
	public void vote5(){
		if(fail==1){
			try{
				Boolean oine = one.pop();
				Boolean two = one.pop();
				Boolean three = one.pop();
				Boolean four = one.pop();
				Boolean five = one.pop();
				if((oine&two&three==true)|(oine&two&four==true)|(oine&two&five==true)|(oine&three&four==true)|(oine&three&five==true)|(oine&four&five==true)|(two&three&four==true)|(two&three&five==true)|(two&four&five==true)|(three&four&five==true)){
					one.push(true);
				}else{
					one.push(false);
				}
			}catch(EmptyStackException e){
				clear();
				fail = 0;
			}
		}
	}
	public void clear(){
		one.clear();
		fail=1;
	}
	public Boolean result (){
		if(fail==1){
			return one.pop();
		}else{
			return null;
		}
	}
}