#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 op;
    double a, b, value;

    reset();

    while(1) {

        scanf("%d", &op);

        if(op == 9) {
            break;
        }

        switch(op) {

           
            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);
                break;
        }
    }

    answer();

    return 0;
}


void push(double value)
{
    if(isFull() == 1) {
        return;
    }
    else {
        stack[sp] = value;
        sp++;
        printf("data:%f\n", value);
    }
}


double pop(void)
{
    if(isEmpty() == 1) {
        return 0;
    }
    else {
        sp--;
        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("answer:%f\n", pop());
}

void reset(void)
{
    sp = 0;
}