#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 resp;
        double value, a, b;

        scanf("%d", &resp);

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

            case 9:
                break;
        }

        if(resp == 9) 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)
{
    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("\nanswer:%f\n", stack[sp-1]);
    }
}

void reset(void)
{
    sp = 0;

}