diff --git a/du3/program.c b/du3/program.c
index e5e24a7..c6f253e 100644
--- a/du3/program.c
+++ b/du3/program.c
@@ -1,68 +1,77 @@
-#include <string.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 
-#define LIST_SIZE 100
+#define STACK_SIZE 10
 
-struct listok {
-   char nazov[101];
-   float cena;
+struct stack {
+   float values[STACK_SIZE];
+   int size;
 };
 
-int add_listok(struct listok *p, int *n){
-   if (fgets(p[*n].nazov, 101, stdin) == NULL){
-      return 0;
+void print_stack(struct stack *s) {
+   for (int i = 0; i < s->size; i++) {
+      printf("%.2f ", s->values[i]);
    }
-
-   p[*n].nazov[strcspn(p[*n].nazov, "\n")] = 0;
-
-   if (scanf("%f", &p[*n].cena) != 1){
-      return 0;
-   }
-
-   getchar();
-   *n = *n + 1;
-   return 1;
+   printf("\n");
 }
 
-int compare(struct listok *a, struct listok *b){
-   if (a->cena > b->cena){
-      return 1;
+void push_stack(struct stack *s, float value) {
+   if (s->size >= STACK_SIZE) {
+      printf("no input\n");
+      exit(0);
    }
-   if (a->cena < b->cena){
-      return -1;
-   }
-   return strcmp(a->nazov, b->nazov);
+   s->values[s->size] = value;
+   s->size++;
 }
 
-void sort_listok(struct listok *p, int n){
-   for (int i = 0; i < n - 1; i++){
-      for (int j = i + 1; j < n; j++){
-         if (compare(&p[i], &p[j]) > 0){
-            struct listok tmp = p[i];
-            p[i] = p[j];
-            p[j] = tmp;
+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("no input\n");
+            exit(0);
          }
+
+         float b = pop_stack(&s);
+         float a = pop_stack(&s);
+         float result;
+
+         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("no input\n");
+            exit(0);
+         }
+         push_stack(&s, val);
+         print_stack(&s);
       }
    }
-}
-
-void print_listok(struct listok *p, int n){
-   for (int i = 0; i < n; i++){
-      printf("%s\n", p[i].nazov);
-      printf("%f\n", p[i].cena);
-   }
-}
-
-int main(){
-   struct listok p[LIST_SIZE];
-   int n = 0;
-
-   while (add_listok(p, &n)){
-   }
-
-   sort_listok(p, n);
-   print_listok(p, n);
 
    return 0;
 }