George and Accommodation
CodeForces - 467A
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
挺随便的一道题
注意输入带空格其实实际上是有两个数据
主要问题是
注意有两个人一起住宿！
#include<iostream>
using namespace std;
int main()
{
int r,pi,qi,m=0; //r代表room有多少间,pi代表房间目前有多少人住，qi代表房间可容纳多少人，m代表可以住进去的房间个数；
cin >> r;
for (int i = 0; i < r ; i++) //反复输入pi，qi
{
cin >> pi >> qi;
if ( pi <= qi-2)
{
m++;
}
}
cout << m;
return 0;
}