commit eb88512ab3c6dfec4e73fe95da3f36ba1219b991
Author: Matej Chmelár <mc892yx@omega.tuke.sk>
Date:   Mon Mar 1 18:35:22 2021 +0100

    first push

diff --git a/du1/program.c b/du1/program.c
new file mode 100644
index 0000000..90318a3
--- /dev/null
+++ b/du1/program.c
@@ -0,0 +1,18 @@
+#include <stdio.h>
+#include <ctype.h>
+
+int main() {
+    int c = 0;
+    while(1) {
+        c = getchar();
+    }
+    if (c == islower(c)) {
+        c = toupper(c);
+    }
+    else if (c == isupper(c)) {
+        c = tolower(c);
+    }
+    return 0;
+}
+
+