Update SHORT_NOTES.md

Author: raihankhan

SHORT_NOTES.md

@@ -51,7 +51,7 @@ If  n = P1^a1 * P2^a2 * P3^a3 ................ Pk^ak , where P1,P2....Pk are pri
 A simple source code in cpp can be found [here](https://github.com/raihankhan/DATA-STRUCTURE-AND-ALGORITHMS/blob/master/Number%20Theory/Euler's%20Phi.cpp)
 
 Another important characteristics of Phi function is :
-###### Summation of all the Phi of divisors of n is equal to n
+#### Summation of all the Phi of divisors of n is equal to n
 
 If N has 4 divisors d1,d2,d3 and d4 then
 Phi(d1) + Phi(d2) + Phi(d3) + Phi(d4) = n