restructure zeta/** to storage/zeta/**

storage/zeta/py/completed/2839.py

@@ -0,0 +1,9 @@
+N = int(input())
+a = 0
+while (N%5+5*a)%3 != 0 :
+    a+=1
+
+if N//5-a < 0:
+    print(-1)
+else:
+    print((N%5+5*a)//3 + (N//5-a))