diff --git a/zpevnik.tex b/zpevnik.tex
index ee22132..f721433 100644
--- a/zpevnik.tex
+++ b/zpevnik.tex
@@ -1,4 +1,5 @@
 \documentclass[a5paper,10pt]{book}
+\usepackage{ifpdf}
 \usepackage[chorded]{songs}
 \usepackage[czech]{babel}
 \usepackage[utf8]{inputenc}