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.
Sample test(s)
Input
3 1 1 2 2 3 3
Output
0
Input
3 1 10 0 10 10 10
Output
2
题意：有n个寝室，一共可以住qi,已经住了pi个，问再来两个可以住进去几个寝室
思路：直接计算的大水题
#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
int main() {
int n;
scanf("%d", &n);
int p, q, ans = 0;
for (int i = 0; i < n; i++) {
scanf("%d%d", &q, &p);
if (p - q >= 2)
ans++;
}
printf("%d\n", ans);
return 0;
}