George and Accommodation

文章目录

一、George and Accommodation

总结

一、George and Accommodation

本题链接：George and Accommodation

题目：

A. George and Accommodation

time limit per test1 second

memory limit per test256 megabytes

inputstandard input

outputstandard output

George has recently entered the BSUCP (Berland State University for Cool Programmers). George has a friend Alex who has also entered the university. Now they are moving into a dormitory.

George and Alex want to live in the same room. The dormitory has n rooms in total. At the moment the i-th room has pi people living in it and the room can accommodate qi people in total (pi ≤ qi). Your task is to count how many rooms has free place for both George and Alex.

Input

The first line contains a single integer n (1 ≤ n ≤ 100) — the number of rooms.

The i-th of the next n lines contains two integers pi and qi (0 ≤ pi ≤ qi ≤ 100) — the number of people who already live in the i-th room and the room’s capacity.

Output

Print a single integer — the number of rooms where George and Alex can move in.

Examples

input

3

1 1

2 2

3 3

output

0

input

3

1 10

0 10

10 10

output

2

本博客给出本题截图：

题意：如果q[i] - p[i] >= 2即找到一组解，问一共有多少组解

AC代码

#include <iostream>
using namespace std;
const int N = 110;
int p[N], q[N];
int res;
int main()
{
    int n;
    cin >> n;
    for (int i = 0; i < n; i ++ )
    {
        cin >> p[i] >> q[i];
        if (q[i] - p[i] >= 2)
            res ++;
    }
    cout << res << endl;
    return 0;
}

总结

水题，不解释