diff --git a/du1/program.c b/du1/program.c
new file mode 100644
index 0000000..0ae1e8d
--- /dev/null
+++ b/du1/program.c
@@ -0,0 +1,57 @@
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <ctype.h>
+#include <stdbool.h>
+
+int GetTypZnaku(int vstup);
+
+int main()
+{
+    int vstup = 0;
+    int pocetRiadkov = 0;
+    while (1)
+    {
+        //helper lok. premeny
+        bool mozeBytPrinted = false;
+        int vysChar = 0;
+
+        //scanning faza programu
+        vstup = getchar();
+
+        if (vstup == -1) { break;} //ak EOF (End Of File), resp. koniec suboru
+        if (vstup == '\n')  // ak NewLine char, resp. koniec riadku
+        { 
+            pocetRiadkov += 1;
+            mozeBytPrinted = false;
+        }
+
+        //ak vstup == malemu pismenu
+        if (GetTypZnaku(vstup) == 0)
+        {
+            vysChar = toupper(vstup);
+        }
+        //ak vstup == velke pismeno
+        else if (GetTypZnaku(vstup) == 1)
+        {
+            vysChar = tolower(vstup);
+        }
+        //ak NIE je to pismeno (a zaroven NIE koniec riadku - resp. NewLine character)
+        else if (GetTypZnaku(vstup) == 2 && vstup != '\n')
+        {
+            mozeBytPrinted = false;
+        }
+
+        //output charakteru (ak je teda charakter...)
+        if (mozeBytPrinted) { putchar(vysChar);}
+    }
+    printf("%d", pocetRiadkov);
+    return 0;
+}
+int GetTypZnaku(int vstup)
+{
+    if (islower(vstup) != 0) {  return 0;}
+    if (isupper(vstup) != 0) {  return 1;}
+    if (isalpha(vstup) == 0) {  return 2;}
+    return -1;
+}
\ No newline at end of file