#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 a, b;

    reset();

    while(1){
        scanf("%d", &command);

        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", &a);
                push(a);
                break;

            case 9:
                break;
        }

        if(command == 9)
            break;
    }

    answer();

    return 0;
}

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

double pop(void)
{
    double value;

    if(!isEmpty()){
        sp--;
        value = stack[sp];
        return value;
    }

    return 0;
}

int isFull(void)
{
    return sp == SIZE;
}

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

void answer(void)
{
    if(!isEmpty()){
        printf("answer:%f\n", stack[sp - 1]);
    }
}

void reset(void)
{
    sp = 0;
}