# codeforces467-A水题

A. George and Accommodation
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard 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
Copy
31 12 23 3
output
Copy
0
input
Copy
31 100 1010 10
output
Copy
2
#include<iostream>
using namespace std;

int main()
{
int n,p,q,num = 0;
cin >> n;
while(n--)
{
cin >> p >> q;
if(q - p >= 2)
num++;
}
cout << num << endl;
return 0;
}

posted @ 2019-11-05 20:36  恶魔岛  阅读(...)  评论(... 编辑 收藏