diff --git a/du3/program.c b/du3/program.c
index d64438b..60be17b 100644
--- a/du3/program.c
+++ b/du3/program.c
@@ -10,6 +10,10 @@ int day=0;
 int m=0;
 int y=0;
 sscanf(str, "%d.%d.%d", &day, &m, &y);
+if(day>28 && m==2 &&(y%400==0 ||(y%100!=0 && y%4==0))){
+    printf("Nespravny datum");
+    return 0;
+}  
 day+=7;
 if(m%2!=0 && day>31){
     day-=31;