Codeforces刷题之路——467A George and Accommodation

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

3
1 1
2 2
3 3

output

0

input

3
1 100 1010 10

output

2

解题思路：这是一道水题，大致意思为求出能同时入住George和Alex的房间有多少间。

以下为解题代码 (java实现)

import java.util.Scanner;

public class Main {

public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner scanner = new Scanner(System.in);
int n = scanner.nextInt();
int count = 0;
int p = 0;
int q = 0;
for(int i = 0; i < n;i++){
p = scanner.nextInt();
q = scanner.nextInt();
scanner.nextLine();
if((q-p) >= 2){
count++;
}
}
System.out.println(count);
}
}