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

#define LINE_SIZE 100
#define STACK_SIZE 10

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

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

void push_stack(struct stack* stack, float value) {
    if (stack->size >= STACK_SIZE) {
        printf("Chyba: zasobnik je plny\n");
        exit(1);
    }
    stack->values[stack->size] = value;
    stack->size++;
}

float pop_stack(struct stack* stack) {
    if (stack->size == 0) {
        printf("Chyba: zasobnik je prazdny\n");
        exit(1);
    }
    stack->size--;
    return stack->values[stack->size];
}

int is_operator(char* input) {
    return (strcmp(input, "+") == 0 || strcmp(input, "-") == 0 ||
            strcmp(input, "*") == 0 || strcmp(input, "/") == 0);
}

void perform_operation(struct stack* stack, char* operator) {
    if (stack->size < 2) {
        printf("Chyba: nedostatok operandov\n");
        exit(1);
    }

    float b = pop_stack(stack);
    float a = pop_stack(stack);
    float result;

    if (strcmp(operator, "+") == 0) {
        result = a + b;
    } else if (strcmp(operator, "-") == 0) {
        result = a - b;
    } else if (strcmp(operator, "*") == 0) {
        result = a * b;
    } else if (strcmp(operator, "/") == 0) {
        if (b == 0) {
            printf("Chyba: delenie nulou\n");
            exit(1);
        }
        result = a / b;
    } else {
        printf("Chyba: neplatna operacia\n");
        exit(1);
    }

    push_stack(stack, result);
}

int main() {
    char input[LINE_SIZE];
    float value;
    struct stack mystack;
    memset(&mystack, 0, sizeof(struct stack));

    while (fgets(input, LINE_SIZE, stdin) != NULL) {
        // Remove trailing newline character
        input[strlen(input) - 1] = '\0';

        // Try to parse input as a number
        if (sscanf(input, "%f", &value) == 1) {
            push_stack(&mystack, value);
        }
        // If it's not a number, check if it's a valid operator
        else if (is_operator(input)) {
            perform_operation(&mystack, input);
        }
        // Invalid input
        else {
            printf("Chyba: neplatny vstup\n");
            return 1;
        }

        // Print stack after each input
        print_stack(&mystack);
    }

    return 0;
}