#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)
{
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らない\n");
}else{
stack[sp++] = value;
}
}

double pop(void)
{
if( isEmpty() ){
printf("スタックが空で取り出せない\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();
}