#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define STACK_SIZE 10

struct stack{
    float *values;
    int size;
    int capacity;
};

struct stack* create_stack (int capacity) {
    struct stack* s = malloc (sizeof(struct stack));
    if (s==NULL) {
        printf("Error!\n");
        exit(1);
    }
    s->values = malloc(capacity * sizeof(float));
    if (s->values==NULL) {
        printf("Error!\n");
        free(s);
        exit(1);
    }
    s->size = 0;
    s->capacity = capacity;
    return s;
}

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

float pop_stack(struct stack* s) {
    if (s->size <= 0) {
        printf("Erroe!\n");
        exit(1);
    }
    s->size--;
    return s->values[s->size];
}

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

void destroy_stack (struct stack* s) {
    free(s->values);
    free(s);
}

int main() {
    struct stack* s = create_stack(STACK_SIZE);
    char input[101];
    while (scanf("%s", input)==1) {
        char *end;
        float value = strtof(input, &end);
        if (*end == '\0') {
            push_stack(s, value);
            print_stack(s);
        } else if (strcmp(input, "+")==0 || strcmp(input, "-")==0 || strcmp(input, "*")==0 || strcmp(input, "/")==0) {
            if (s->size < 2) {
                printf("not enough operands\n");
                destroy_stack(s);
                return 0;
            }
            
            float b = pop_stack(s);
            float a = pop_stack(s);
            float result = 0;

            if (strcmp(input, "+")==0) {
                result = a+b;
            }
            if (strcmp(input, "-")==0) {
                result = a - b;
            }
            if (strcmp(input, "*")==0) {
                result = a * b;
            }
            if (strcmp(input, "/")==0) {
                if (b==0) {
                    printf("division by zero\n");
                    destroy_stack(s);
                    return 0;
                }
                result = a/b;
            }
            push_stack(s, result);
            print_stack(s);
        }
        else {
                printf("bad input\n"); 
                destroy_stack(s);
                return 0;
        }
    }
    destroy_stack(s);
    printf("no input\n");
    return 0;

}