diff --git a/book/book.tex b/book/book.tex
index 98052b39..8a422b9f 100644
--- a/book/book.tex
+++ b/book/book.tex
@@ -2867,7 +2867,7 @@ \section{Exercises}
 
 Of course, one option is to run Dijkstra's algorithm $n$ times,
 once for each starting node.  And for some applications, that's
-probably good enough.  But there are are more efficient alternatives.
+probably good enough.  But there are more efficient alternatives.
 
 Find an algorithm for the all-pairs shortest path problem and
 implement it.  See