CodeForces

B. Karen and Coffee

time limit per test

2.5 seconds

memory limit per test

512 megabytes

input

standard input

output

standard output

To stay woke and attentive during classes, Karen needs some coffee!

Karen, a coffee aficionado, wants to know the optimal temperature for brewing the perfect cup of coffee. Indeed, she has spent some time reading several recipe books, including the universally acclaimed "The Art of the Covfefe".

She knows n coffee recipes. The i-th recipe suggests that coffee should be brewed between li and ri degrees, inclusive, to achieve the optimal taste.

Karen thinks that a temperature is admissible if at least k recipes recommend it.

Karen has a rather fickle mind, and so she asks q questions. In each question, given that she only wants to prepare coffee with a temperature between a and b, inclusive, can you tell her how many admissible integer temperatures fall within the range?

Input

The first line of input contains three integers, n, k (1 ≤ k ≤ n ≤ 200000), and q (1 ≤ q ≤ 200000), the number of recipes, the minimum number of recipes a certain temperature must be recommended by to be admissible, and the number of questions Karen has, respectively.

The next n lines describe the recipes. Specifically, the i-th line among these contains two integers li and ri (1 ≤ li ≤ ri ≤ 200000), describing that the i-th recipe suggests that the coffee be brewed between li and ri degrees, inclusive.

The next q lines describe the questions. Each of these lines contains a and b, (1 ≤ a ≤ b ≤ 200000), describing that she wants to know the number of admissible integer temperatures between a and b degrees, inclusive.

Output

For each question, output a single integer on a line by itself, the number of admissible integer temperatures between a and b degrees, inclusive.

Examples

input

3 2 491 9492 9797 9992 9493 9795 9690 100

output

3304

input

2 1 11 1200000 20000090 100

output

0

题意：

给出n个推荐煮咖啡的温度区间，然后有q个询问，每个询问给出一个区间，问这个区间有几个温度受到推荐次数大于等于k。

解题思路：

据说此题要用线段树。但是有一种奇妙的想法，可以很巧妙的解决。

开一个标记数组，每次输入适宜的温度区间，就在a[l]++;在a[r+1]--;区间输入完毕后，从前到后进行一边求和。看图理解。

标记的时候是a[l]++,但是右端点是a[r+1]--;为什么？这个需要自己想明白。

看代码：

# include <cstdio># include <cstring>using namespace std;const int maxn = 200005;int main(){int n,k,m;int a[maxn];int l,r;memset(a,0,sizeof(a));scanf("%d %d %d",&n,&k,&m);for(int i = 0;i < n;i++)  //标记区间{scanf("%d %d",&l,&r);a[l]++;a[r+1]--;}for(int i = 1;i < maxn;i++)  //根据标记求出每个温度出现次数{//printf("%d ",a[i]);a[i] += a[i-1];}for(int i = 0;i < maxn;i++)  //出现次数大于等于k的变为一{if(a[i] >= k){a[i] = 1;}else{a[i] = 0;}}//printf("\n");for(int i = 1;i < maxn;i++)  //求前缀和{a[i] += a[i-1];}for(int i = 0;i < m;i++){scanf("%d %d",&l,&r);printf("%d\n",a[r]-a[l-1]);  //查询输出前缀和的差就是答案}return 0;}