diff --git a/du3/program.c b/du3/program.c
index c274ab5..af0090a 100644
--- a/du3/program.c
+++ b/du3/program.c
@@ -5,7 +5,7 @@ int main(){
     int month;
     int year;
     scanf("%d.%d.%d", &day, &month, &year);
-    if(day < 1 || day > 31 || month < 1 || month > 12){
+    if(day < 1 || day > 31 || month < 1 || month > 12 || year < 0){
         puts("Nespravny datum");
         return 0;
     }
@@ -60,4 +60,4 @@ if(day > 30){
     else{
         printf("%d.%d.%d\n\n", day, month, year);
     }
-}
+}
\ No newline at end of file