diff --git a/110A.py b/110A.py
index 6b58150..c61c6c9 100644
--- a/110A.py
+++ b/110A.py
@@ -1,9 +1,9 @@
 #Question: https://codeforces.com/problemset/problem/110/A 
 
-n = input()
+num = input()
 count = 0
-for i in range(len(n)):
-    if (n[i]) == '4' or (n[i]) == '7':
+for i in range(len(num)):
+    if (num[i]) == '4' or (num[i]) == '7':
         count = count+1       
 if count == 7 or count == 4  :
     print("YES")