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

#define STACK_SIZE 100

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

int main(){
    struct stack mystack;
    memset(&mystack,0,sizeof(struct stack));
    char vstup[STACK_SIZE];
    int counter = 0;
    while(1){
        if (fgets(vstup, sizeof(vstup), stdin) == NULL) {
            printf("no input\n");
            return 0;
        }
        if(vstup[0] == '-' || vstup[0] == '+' || vstup[0] == '*' || vstup[0] == '/'){
            if(counter < 2){
                printf("not enough operands\n");
                return 0;
            }
            if(vstup[0] == '-'){
                mystack.values[counter-2] = mystack.values[counter-2] - mystack.values[counter-1];
                mystack.values[counter-1] = 0;
                counter--;
            }
                if(vstup[0] == '/'){
                if(mystack.values[counter-1] == 0){
                    printf("division by zero\n");
                    return 0;
                }
                mystack.values[counter-2] = mystack.values[counter-2] / mystack.values[counter-1];
                mystack.values[counter-1] = 0;
                counter--;
            }
                if(vstup[0] == '*'){
                mystack.values[counter-2] = mystack.values[counter-2] * mystack.values[counter-1];
                mystack.values[counter-1] = 0;
                counter--;
            }
                if(vstup[0] == '+'){
                mystack.values[counter-2] = mystack.values[counter-2] + mystack.values[counter-1];
                mystack.values[counter-1] = 0;
                counter--;
                }
            }
        else{
            char *endptr;
            float cislo = strtof(vstup, &endptr);
            if (endptr == vstup || *endptr != '\n') {
                printf("bad input\n");
                return 0;
            }
            mystack.values[counter] = cislo;
            counter++;
        }
        mystack.size = counter;
        for(int i =0; i < counter;i++){
            printf("%.2f ", mystack.values[i]);
        }
        printf("\n");
    }
}