#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 n;
    double a, b, x;

    reset();

    while(1){
        scanf("%d", &n);
        if(n == 9){
        	break;
        	
        }

        switch(n){
            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", &x);
                push(x);
                printf("data:%f\n", x);
                break;


        }

    }

    answer();

    return 0;
}

void push(double value)
{
    if(isFull() == 0){
        stack[sp++] = value;
    }
}

double pop(void)
{
    if(isEmpty() == 0){
        return stack[--sp];
    }
    return 0;
}

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

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

void answer(void)
{
    printf("answer:%f\n", pop());
}

void reset(void)
{
    sp = 0;
}