#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 resp;
    double data, cal1, cal2;

    reset();

   while(1){
        double data;
        double cal1, cal2;
        int resp;
    
        scanf("%d", &resp);

        if( resp == 9 )  break;

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

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

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

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

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

    answer();

    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)
{
    if(sp >= SIZE){
        return 1;
    }else{
        return 0;
    }
}

int isEmpty(void)
{
    if(sp <= 0){
        return 1;
    }else{
        return 0;
    }
}

void answer(void)
{
    printf ("\n");
    printf ("answer:%lf\n", stack[0]);
}

void reset(void)
{
    while(!isEmpty())
        pop();
}