#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 c;
        scanf("%d",&c);
        switch (c) {
            case 1: {
                double b=pop();
                double a=pop();
                push(a+b);
                break;
            }
            case 2: {
                double b=pop();
                double a=pop();
                push(a-b);
                break;
            }
            case 3: {
                double b=pop();
                double a=pop();
                push(a*b);
                break;
            }
            case 4: {
                double b=pop();
                double a=pop();
                if (b==0) {
                    printf("0で割ることはできません。\n");
                    reset();
                } else {
                    push(a/b);
                }
                break;
            }
            case 5: {
                double x;
                scanf("%lf",&x);
                printf("date:%lf\n",x);
                push(x);
                break;
            }
            case 9: {
                answer();
                return 0;
            }
        }
    }
    return 0;
}
 
void push(double value)
{
    if(isFull()){
        printf("スタックが満杯で入りませんでした。\n");
    }
    else{
        stack[sp++]=value;
    }
}
 
double pop(void)
{
    if(isEmpty()){
        printf("スタックが空で取り出せませんでした\n");
        return 0;
    }
    else{
        return stack[--sp];
    }
}
 
int isFull(void)
{
    return sp >= SIZE;
}
 
int isEmpty(void)
{
    return sp <= 0;
}
 
void answer(void)
{
    if (sp == 1) {
        printf("answer:%lf\n", stack[0]);
    } else if (isEmpty()) {
        printf("スタックが空です。\n");
    } else {
        printf("スタックに複数の値が残っています。\n");
    }
}
 
void reset(void)
{
    sp=0;
}

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