#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 resp;
			double data, data1,data2;
printf("1:+,2:-,3:*,4:/,5:input,9:kekka");
scanf("%d",&resp);
if(resp==9)break;
switch(resp){
case 1:
data1=pop();
data2=pop();
push(data1+data2);
break;

case 2:
data1=pop();
data2=pop();
push(data2-data1);
break;

case 3:
data1=pop();
data2=pop();
push(data1*data2);
break;

case 4:
data1=pop();
data2=pop();
push(data2/data1);
break;

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

}
answer();
return 0;

}
void push(double value){if(sp>=SIZE){
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(sp<=0){
 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("answer%lf\n",stack[sp-1]);
}
void reset(void){sp=0;
}