Cow Lineup
时间限制:C/C++/Rust/Pascal 1秒,其他语言2秒
空间限制:C/C++/Rust/Pascal 32 M,其他语言64 M
64bit IO Format: %lld

题目描述

Farmer John has hired a professional photographer to take a picture of some of his cows.  Since FJ's cows represent a variety of different breeds, he would like the photo to contain at least one cow from each distinct breed present in his herd.
FJ's N cows are all standing at various positions along a line, each described by an integer position (i.e., its x coordinate) as well as an integer breed ID.  FJ plans to take a photograph of a contiguous range of cows along the line.  The cost of this photograph is equal its size -- that is, the difference between the maximum and minimum x coordinates of the cows in the range of the photograph. 
Please help FJ by computing the minimum cost of a photograph in which there is at least one cow of each distinct breed appearing in FJ's herd.

输入描述:

* Line 1: The number of cows, N (1 <= N <= 50,000).
* Lines 2..1+N: Each line contains two space-separated positive integers specifying the x coordinate and breed ID of a single cow. Both numbers are at most 1 billion.

输出描述:

* Line 1: The smallest cost of a photograph containing each distinct breed ID.
示例1

输入

复制
6
25 7
26 1
15 1
22 3
20 1
30 1

输出

复制
4

说明

There are 6 cows, at positions 25,26,15,22,20,30, with respective breed IDs
7,1,1,3,1,1.
The range from x=22 up through x=26 (of total size 4) contains each of the
distinct breed IDs 1, 3, and 7 represented in FJ's herd.