diff --git a/get_function_len.py b/get_function_len.py
new file mode 100644
index 0000000..acd271c
--- /dev/null
+++ b/get_function_len.py
@@ -0,0 +1,46 @@
+import lzma
+import sys
+import os
+
+
+def get_rank_file_object(args_count, rank_ind):
+    base_name = "base_{}_rank_{}.txt".format(args_count, rank_ind)
+    if os.path.exists(base_name):
+        return open(base_name, 'rb')
+    elif os.path.exists(base_name + ".xz"):
+        return lzma.open(base_name + ".xz", 'rb')
+    else:
+        print("No results file for {} arguments rank {}".format(args_count, rank_ind))
+        sys.exit(1)
+
+def is_function_exists(function_number, file_object):
+    file_object.seek(function_number // 8)
+    result_byte = ord(file_object.read(1))
+    return (result_byte >> (7 - function_number % 8)) % 2 == 1
+
+
+def function_values_to_number(values):
+    assert set(values).issubset({'0','1'})
+    res = 0
+    for ch in values:
+        res *= 2
+        if ch == '1':
+            res += 1
+    return res
+
+
+def main():
+    args_count = {
+        8: 3,
+        16: 4,
+        32: 5,
+    }[len(sys.argv[1])]
+    function_number = function_values_to_number(sys.argv[1])
+    print("Function number is {}".format(function_number))
+    for rank_ind in range(1, 10):
+        if is_function_exists(function_number, get_rank_file_object(args_count, rank_ind)):
+            print("Result len is {}".format(rank_ind))
+            return
+
+if __name__ == "__main__":
+    main()