diff --git a/README.md b/README.md
index b103466139..b7f004eed4 100644
--- a/README.md
+++ b/README.md
@@ -6,11 +6,11 @@ A calculator that calculates simple interest given principal, annual rate of int
 
 ```
 Input:
-   p, principal amount
-   t, time period in years
-   r, annual rate of interest
+   P, principal amount
+   T, time period in years
+   R, annual rate of interest
 Output
-   simple interest = p*t*r
+   simple interest = P*T*R
 ```
 
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