diff --git a/README.md b/README.md
index 9608fad..ad85776 100644
--- a/README.md
+++ b/README.md
@@ -20,7 +20,7 @@ For extra payments towards principal, invoking the script will look like:
 
     python src/amort.py -p {principal} -i {interest rate} -t {years} --extra-payments extra_payments.json
 
-A valid json file contains an list named `extra-payments`. Each element is an object with the attributes `payment-number` and `amount`.
+A valid json file contains a list named `extra-payments`. Each element is an object with the attributes `payment-number` and `amount`.
 
     {
         "extra-payments" : [