diff --git a/Math/Prime_Factorization/README.md b/Math/Prime_Factorization/README.md
index 9d9cd83a4..4ac39c878 100644
--- a/Math/Prime_Factorization/README.md
+++ b/Math/Prime_Factorization/README.md
@@ -8,3 +8,5 @@ Second: Using the prime numbers to reduce the the given number and thus find all
 
 The complexity of the solution involves approx. O(n logn) in calculating sieve of eratosthenes
 O(log n) in calculating the prime factors of the number. So in total approx. O(n logn).
+
+**Requirements: For compile you need the compiler flag for C++ 11**