diff --git a/app.py b/app.py
new file mode 100644
index 0000000..cc84de0
--- /dev/null
+++ b/app.py
@@ -0,0 +1,20 @@
+print('1. solve hypotenuse')
+print('2. solve short side')
+print('3. quit')
+
+while True then
+  choice < - input('choice: ')
+   if choice == 1 then
+     a = input('a: ')
+      b = input('b: ')
+       c = √(a*a+b*b)
+        print('c:', c)
+    elif choice == 2 then
+     b = input('b: ')
+      c = input('c: ')
+       a = √(c*c-b*b)
+        print('a:', a)
+    else then
+     quit()
+    endif
+endwhile