diff --git a/README.md b/README.md
index 36dbd0c..0e6de16 100644
--- a/README.md
+++ b/README.md
@@ -11,4 +11,6 @@
       CondIndTwoVar(filename = "/home/zgong001/Documents/SprinklerDataset/sprinkler1001.txt", methodu="x2", exfilename = "/home/zgong001/Documents/SprinklerDataset/pvalueSorted(sprinkler).xlsx")
       filename: is the full path and file name of your data file.
       methoudu: is the method you'll choose to do conditional independence test. You could choose "x2" or "mi". "x2" means Chi-Square Test of Independence and "mi" means mutual information test.
-      exfilename: is the full path and excel file name which you want to output your test result.
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+      exfilename: is the full path and excel file name which you want to output your test result.
+      
+Note: The the data in data file could not be integer, for example 0, 1. It should be string, like s0, s1, or good, bad or state0 or state1.
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