#include <stdio.h>

#define SIZE 10
double stack[SIZE];
int sp;

void push(double value);
double pop(void);
int isFull(void);
int isEmpty(void);
void answer(void);
void reset(void);

int main(void) {
	reset();
	while(1){
		double data;
		double cal1,cal2;
		int resp;
		
		scanf("%d",&resp);
		
		if(resp==9)break;
		
		switch(resp){
			case 1:cal1=pop();
			       cal2=pop();
			       push(cal2+cal1);
			       break;
			       
			case 2:cal1=pop();
			       cal2=pop();
			       push(cal2-cal1);
			       break;
			       
			case 3:cal1=pop();
			       cal2=pop();
			       push(cal2*cal1);
			       break;
			       
			case 4:cal1=pop();
			       cal2=pop();
			       push(cal2/cal1);
			       break;
			       
			case 5:printf("data:");
			       scanf("%lf",&data);
			       push(data);
			       printf("%lf\n",data);
			       break;
		}
	}
	answer();
	return 0;
}

void push(double value){
	if(isFull()){
		printf("スタックが満杯で入りませんでした\n");
	}else{
		stack[sp++]=value;
	}
}

double pop(void){
	if(isEmpty()){
		printf("スタックが空で取り出せませんでした\n");
		return 0;
	}else{
		return stack[--sp];
	}
}

int isFull(void){
	if(sp>=SIZE){
		return 1;
	}else{
		return 0;
	}
}

int isEmpty(void){
	if(sp<=0){
		return 1;
	}else{
		return 0;
	}
}

void answer(void){
	printf("\n");
	printf("answer:%lf\n",stack[0]);
}

void reset(void){
	while(!isEmpty())
	pop();
}