diff --git a/cv3/program.c b/cv3/program.c
index 251026c..31e5b27 100644
--- a/cv3/program.c
+++ b/cv3/program.c
@@ -1,6 +1,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <math.h>
 
 #define MAX_RAZMER 10
 
@@ -94,6 +95,10 @@ int main() {
                 exit(1);
             }
             double a = pop(&stek);
+            if (b == 0) {
+                printf("division by zero\n");
+                exit(1);
+            }
             push(&stek, a / b);
         } else {
             printf("no input\n");