diff --git a/homeworks/19_Lachezar_Lazarov/num_ways.py b/homeworks/19_Lachezar_Lazarov/num_ways.py
new file mode 100644
index 0000000..12b0479
--- /dev/null
+++ b/homeworks/19_Lachezar_Lazarov/num_ways.py
@@ -0,0 +1,9 @@
+M = input("Stairs to climb: ")
+
+def num_ways(n):
+    if n == 0 or n == 1:
+        return 1
+    else:
+        return num_ways(n-1) + num_ways(n-2)
+
+print(num_ways(int(M)))
diff --git a/homeworks/19_Lachezar_Lazarov/replace1.py b/homeworks/19_Lachezar_Lazarov/replace1.py
new file mode 100644
index 0000000..00a32a2
--- /dev/null
+++ b/homeworks/19_Lachezar_Lazarov/replace1.py
@@ -0,0 +1,14 @@
+def replace1(list1, find, replace):
+    for i in range(0, len(list1)):
+        if list1[i] == find:
+            list1[i] = replace
+        try:
+            if len(list1[i]) > 1:
+                list1[i] = replace1(list1[i], find, replace)
+        except:
+            continue
+    return list1
+    
+list1 = [ 'a', 1, [ ['a', 'b'], 1], ([1, 3, 'a'], 'b')]
+res = replace1(list1, 'a', 'c')
+print(res) # => [ 'c', 1, [ ['c', 'b'], 1], ([1, 3, 'c'], 'b')]