diff --git a/README.md b/README.md
index 072d1e6..9a6d4c6 100644
--- a/README.md
+++ b/README.md
@@ -21,7 +21,7 @@ Segment Tree (one-dimensional)
 
     from segment_tree import *
     array = [3, 1, 5, 3, 13, 7, 2, 7, 2]
-    tree = SegmentTree(array)
+    t = SegmentTree(array)
 
     t.query(1, 3, "sum") # 9
     t.update(0, 10) # [10, 1, 5, 3, 13, 7, 2, 7, 2]
@@ -56,11 +56,11 @@ Multidimensional Segment Tree (alpha version, might have bugs)
 ```python
     from segment_tree import *
     a = [[[1, 2], [1, 3]], [[-1, -2], [-1, -3]]]
-    tree = MultidimensionalSegmentTree(a)
+    t = MultidimensionalSegmentTree(a)
 
-    tree.query([(0, 1), (0, 0), (0, 0)], max) # 1
-    tree.query([(1, 1), (0, 1), (0, 1)], sum) # -7
-    tree.query([(0, 1), (1, 1), (0, 1)], min) # -3
+    t.query([(0, 1), (0, 0), (0, 0)], max) # 1
+    t.query([(1, 1), (0, 1), (0, 1)], sum) # -7
+    t.query([(0, 1), (1, 1), (0, 1)], min) # -3
 ```
 
 ## Operations and their complexity
diff --git a/segment_tree/operations.py b/segment_tree/operations.py
index c176406..0882829 100644
--- a/segment_tree/operations.py
+++ b/segment_tree/operations.py
@@ -18,5 +18,5 @@ def max_multiple(x, count):
 
 
 sum_operation = Operation("sum", sum, add_multiple, 0)
-min_operation = Operation("min", min, min_multiple, 1e9)
-max_operation = Operation("max", max, max_multiple, -1e9)
+min_operation = Operation("min", min, min_multiple, +float('inf'))
+max_operation = Operation("max", max, max_multiple, -float('inf'))
diff --git a/segment_tree/segment_tree.py b/segment_tree/segment_tree.py
index 8b6c3a1..598192f 100644
--- a/segment_tree/segment_tree.py
+++ b/segment_tree/segment_tree.py
@@ -1,4 +1,4 @@
-from segment_tree.operations import *
+from .operations import *
 
 
 class SegmentTree:
diff --git a/setup.py b/setup.py
index c63e029..aa584cd 100644
--- a/setup.py
+++ b/setup.py
@@ -16,4 +16,4 @@
     license='MIT',
     packages=find_packages(exclude=['tests*']),
     keywords='segment, tree, range, rmq, multidimensional',
-    python_requires='>=3')
+    python_requires='>=2.7')