#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){
		int resp;
		double data,cal1,cal2;
		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("data:%f\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:%f\n",stack[0]);
	}
void reset(void){
	while(!isEmpty())
	pop();
}