diff --git a/a1/program.c b/a1/program.c
index 0b2e16c..409f91d 100644
--- a/a1/program.c
+++ b/a1/program.c
@@ -46,6 +46,9 @@ int main() {
 			if(yyyy <= 0){
 		    		che = 1;
 		    	}
+			if(yyyy < 1900 || yyyy > 2100){
+			che = 1;
+			}
                 }
                 counter++;
                 zaciatok_cisla = koniec_cisla + 1;