#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)
{
	int command;
	double value;
	double a, b;
    reset();
    while(1){
    	scanf("%d", &command);
    	if(command == 9){
    		break;
    	}
    	switch(command){
    		case 1:
    		b = pop();
    		a = pop();
    		push(a + b);
    		break;
    			case 2:
    			b = pop();
    			a = pop();
    			push(a -b);
    			break;
    				case 3:
    				b = pop();
    				a = pop();
    				push(a * b);
   					break;
    					case 4:
    					b = pop();
    					a = pop();
    					push(a / b);
    					break;
    						case 5:
    						scanf("%lf", &value);
    						push(value);
    						printf("data:%f\n", value);
    						break;
    	}
    }
    answer();
    return 0;
}
void push(double value){
		if(!isFull()){
			stack[sp] = value;
			sp++;
		}
	}
	double pop(void){
			if(!isEmpty()){
				sp--;
				return stack[sp];
			}
			return 0;
		}
int isFull(void){
	return sp == SIZE;
}
int isEmpty(void){
	return sp == 0;
}
void answer(void){
	printf("answer:%f\n", pop());
}
void reset(void){
	sp = 0;
}