diff --git a/squareroot.sage b/squareroot.sage
index 167c63e..3208c5e 100755
--- a/squareroot.sage
+++ b/squareroot.sage
@@ -3,6 +3,7 @@
 # This implements a prototype of Palash Sarkar's square root algorithm
 # from <https://eprint.iacr.org/2020/1407>, for the Pasta fields.
 
+import sys
 from copy import copy
 from collections import deque
 
diff --git a/squareroottab.sage b/squareroottab.sage
index 6d3e765..969683c 100755
--- a/squareroottab.sage
+++ b/squareroottab.sage
@@ -3,6 +3,7 @@
 # This implements a prototype of Palash Sarkar's square root algorithm
 # from <https://eprint.iacr.org/2020/1407>, for the Pasta fields.
 
+import sys
 from copy import copy
 
 if sys.version_info[0] == 2: