George and Accommodation

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Problem Description
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.

问题链接：(https://vjudge.net/problem/CodeForces-467A)

问题简述：该题要先输入房间数，再输入房间已住人数和房间可容纳的人数。只要房间容纳数-已住人数>2就可以保证题中两人共住一房。

程序说明：我输入房间数后，使用for循环输入每间房的入住情况，再用if语句判断房间容纳数-已住人数是否大于2，如果是，计数变量c就加一。最后输出c。

#include <iostream>
using namespace std;
int main()
{
 int n;
 cin >> n;
 int a, b;
 int c = 0;
 for(int i=0;i<n;i++)
 {
  cin >> a >> b;
  if (b-a>=2)
   c++;
 }
 cout << c;
}