diff --git a/pysollib/pysolrandom.py b/pysollib/pysolrandom.py
index 5ed98188..71bef164 100644
--- a/pysollib/pysolrandom.py
+++ b/pysollib/pysolrandom.py
@@ -248,7 +248,7 @@ PysolRandom = MTRandom
 
 # construct Random from seed string
 def constructRandom(s):
-    m = re.match(r"ms(\d+)\n?\Z", s);
+    m = re.match(r"ms([0-9]+)\n?\Z", s);
     if m:
         seed = long(m.group(1))
         if 0 <= seed <= LCRandom31.MAX_SEED: