diff --git a/cv1/program.c b/cv1/program.c
new file mode 100644
index 0000000..9089da1
--- /dev/null
+++ b/cv1/program.c
@@ -0,0 +1,24 @@
+#include <stdio.h>
+#include <ctype.h>
+
+int main() {
+    int lines_count = -1;
+    int c;
+
+    while ((c = getchar()) != EOF) {
+        if (islower(c)) {
+            putchar(toupper(c));
+        } else if (isupper(c)) {
+            putchar(tolower(c));
+        } else {
+            putchar(c);
+            if (c == '\n') {
+                lines_count++;
+            }
+        }
+    }
+
+    printf("Počet načítaných riadkov: %d\n", lines_count);
+
+    return 0;
+}