diff --git a/common/ngram-mod.cpp b/common/ngram-mod.cpp
index 76f7257f6..1b5a09a5e 100644
--- a/common/ngram-mod.cpp
+++ b/common/ngram-mod.cpp
@@ -1,5 +1,7 @@
 #include "ngram-mod.h"
 
+#include <algorithm>
+
 //
 // common_ngram_mod
 //