#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();
    int n;
double value, a, b;

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", &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)
{
	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("answer:%f\n", stack[sp-1]);
}
}

void reset(void)
{

sp = 0;
}