#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 n;
        double cal1, cal2;

        scanf("%d", &n);

        switch(n){
            case 1:
                cal2 = pop();
                cal1 = pop();
                push(cal1 + cal2);
                break;

            case 2:
                cal2 = pop();
                cal1 = pop();
                push(cal1 - cal2);
                break;

            case 3:
                cal2 = pop();
                cal1 = pop();
                push(cal1 * cal2);
                break;

            case 4:
                cal2 = pop();
                cal1 = pop();
                push(cal1 / cal2);
                break;

            case 5:
            {
                double value;
                scanf("%lf", &value);
                printf("data:%f\n", value);
                push(value);
                break;
            }

            case 9:
                break;
        }

        if(n == 9){
            break;
        }
    }

    answer();

    return 0;
}

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

double pop(void)
{
    double value;

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

    return 0;
}

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)
{
    if(!isEmpty()){
        printf("answer:%f\n", pop());
    }
}

void reset(void)
{
    sp = 0;
}