diff --git a/calculate.py b/calculate.py
new file mode 100644
index 0000000000..6dc22cf124
--- /dev/null
+++ b/calculate.py
@@ -0,0 +1,33 @@
+import circle
+import square
+
+
+figs = ['circle', 'square']
+funcs = ['perimeter', 'area']
+sizes = {}
+
+def calc(fig, func, size):
+	assert fig in figs
+	assert func in funcs
+
+	result = eval(f'{fig}.{func}(*{size})')
+	print(f'{func} of {fig} is {result}')
+
+if __name__ == "__main__":
+	func = ''
+	fig = ''
+	size = list()
+    
+	while fig not in figs:
+		fig = input(f"Enter figure name, avaliable are {figs}:\n")
+	
+	while func not in funcs:
+		func = input(f"Enter function name, avaliable are {funcs}:\n")
+	
+	while len(size) != sizes.get(f"{func}-{fig}", 1):
+		size = list(map(int, input("Input figure sizes separated by space, 1 for circle and square\n").split(' ')))
+	
+	calc(fig, func, size)
+
+
+
diff --git a/circle.py b/circle.py
deleted file mode 100644
index c3eb8647c9..0000000000
--- a/circle.py
+++ /dev/null
@@ -1,10 +0,0 @@
-import math
-
-
-def area(r):
-    return math.pi * r * r
-
-
-def perimeter(r):
-    return 2 * math.pi * r
-
diff --git a/docs/README.md b/docs/README.md
index 63f8727939..73ba4fcb29 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -1,3 +1,9 @@
+# User agreement 
+
+Please check out License Agreement for personal usage terms and limitations
+
+---
+
 # Math formulas
 ## Area
 - Circle: S = πR²
@@ -7,4 +13,6 @@
 ## Perimeter
 - Circle: P = 2πR
 - Rectangle: P = 2a + 2b
-- Square: P = 4a
\ No newline at end of file
+- Square: P = 4a
+
+# Some change for Lesson 6 practice
\ No newline at end of file
diff --git a/square.py b/square.py
deleted file mode 100644
index 0f98724205..0000000000
--- a/square.py
+++ /dev/null
@@ -1,7 +0,0 @@
-
-def area(a):
-    return a * a
-
-
-def perimeter(a):
-    return 4 * a
diff --git a/triangle.py b/triangle.py
new file mode 100644
index 0000000000..fb41f60a52
--- /dev/null
+++ b/triangle.py
@@ -0,0 +1,6 @@
+def area(a, b, c):
+    return (a + b + c) / 2
+
+
+def perimeter(a, b, c):
+    return a + b + c
diff --git a/user_agreement.txt b/user_agreement.txt
new file mode 100644
index 0000000000..5cc86cbd3d
--- /dev/null
+++ b/user_agreement.txt
@@ -0,0 +1,14 @@
+License Agreement
+
+This License Agreement is made and effective as of 10 march 2021 by and between Smartiqa Group, a company organized and existing in Russian Federation, with a registered address at Moscow and User, a company organized and existing in Russian Federation, with a registered address at Moscow.
+
+1.1 “Agreement” means this License Agreement including the attached Schedule.
+
+1.2 “Confidential Information” means information that:
+a. is by its nature confidential;
+b. is designated in writing by Licensor as confidential;
+c. the Licensee knows or reasonably ought to know is confidential;
+d. Information comprised in or relating to any Intellectual Property Rights of Licensor.
+
+1.3 “Asset” means the Asset provided by Licensor as specified in Item 6 of the Schedule in the form as stated in Item 7 of the Schedule.
+