#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define STACK_SIZE 10

struct stack {
   float values[STACK_SIZE];
   int size;
};

void print_stack(struct stack *s) {
   for (int i = 0; i < s->size; i++) {
      printf("%.2f ", s->values[i]);
   }
   printf("\n");
}

void push_stack(struct stack *s, float value) {
   if (s->size >= STACK_SIZE) {
      printf("no input\n");
      exit(0);
   }
   s->values[s->size] = value;
   s->size++;
}

float pop_stack(struct stack *s) {
   if (s->size <= 0) {
      printf("no input\n");
      exit(0);
   }
   s->size--;
   return s->values[s->size];
}

int main() {
   struct stack s;
   s.size = 0;

   char input[100];

   while (scanf("%s", input) == 1) {
      if (strcmp(input, "+") == 0 || strcmp(input, "-") == 0 ||
          strcmp(input, "*") == 0 || strcmp(input, "/") == 0) {

         if (s.size < 2) {
            printf("not enough operands\n");
            exit(0);
         }

         float b = pop_stack(&s);
         float a = pop_stack(&s);
         float result;

         if (strcmp(input, "/") == 0 && b == 0) {
            printf("division by zero\n");
            exit(0);
         }

         if (strcmp(input, "+") == 0) result = a + b;
         else if (strcmp(input, "-") == 0) result = a - b;
         else if (strcmp(input, "*") == 0) result = a * b;
         else result = a / b;

         push_stack(&s, result);
         print_stack(&s);
      } 
      else {
         char *endptr;
         float val = strtof(input, &endptr);
         if (*endptr != '\0') {
            printf("bad input\n");
            exit(0);
         }
         push_stack(&s, val);
         print_stack(&s);
      }
   }

   printf("no input\n");
   return 0;
}