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

#define STACK_SIZE 10
#define LINESIZE 100

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

//zakladne funkcie

void push_stack(struct stack *s, float value) {
    if (s->size >= STACK_SIZE) {
        printf("full stack\n");
        exit(0);
    }
    s->values[s->size] = value;
    s->size++;
}

float pop_stack(struct stack *s) {
    if (s->size <= 0) {
        printf("empty stack\n");
        exit(0);
    }
    s->size--;
    return s->values[s->size];
}

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

//pomocne funkcie

//je retazec cislo
int is_number(const char *str) {
    char *endptr;
    strtof(str, &endptr);
    // ak endptr ukazuje na koniec retazca, bolo to cele cislo
    return (*str != '\0' && *endptr == '\0');
}


int main(void) {
    struct stack s;
    memset(&s, 0, sizeof(struct stack));

    char line[LINESIZE];
    int had_input = 0;

    while (fgets(line, sizeof(line), stdin)) {
	
	had_input = 1;    
	line[strcspn(line, "\n")] = '\0';

        //preskocit prazdny riadok
        if (strlen(line) == 0)
            continue;

        if (is_number(line)) {
            float value = strtof(line, NULL);
            push_stack(&s, value);
        } else if (strlen(line) == 1 && strchr("+-*/", line[0])) {
            //operacia
            if (s.size < 2) {
                printf("not enough operands\n");
                return 0;
            }
            float b = pop_stack(&s);
            float a = pop_stack(&s);
            float result;

            switch (line[0]) {
                case '+': result = a + b; break;
                case '-': result = a - b; break;
                case '*': result = a * b; break;
                case '/':
                    if (b == 0) {
                        printf("division by zero\n");
                        return 0;
                    }
                    result = a / b; break;
                default:
                    printf("Chyba: neznama operacia.\n");
                    return 0;
            }
            push_stack(&s, result);
        } else {
            printf("bad input\n");
            return 0;
        }

        print_stack(&s);
    }

    if (had_input) {
    	printf("no input\n");
    }

    return 0;
}