#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;

    reset();

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

        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", &a);
                push(a);
                printf("data:%f\n", a);
                break;

            case 9:
                goto end;
        }
    }

end:
    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){
    return sp >= SIZE;
}

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

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

void reset(void){
    sp = 0;
}