467A - George and Accommodation.cpp

/*
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
inputCopy
3
1 1
2 2
3 3
outputCopy
0
inputCopy
3
1 10
0 10
10 10
outputCopy
2
*/



#include<bits/stdc++.h>
using namespace std;

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    
   int n;
   cin >> n;
   
   int res = 0;
   
   while (n--) {
   	int p, q;
   	cin >> p >> q;
   	
   	if (q - p >= 2) res++;
   }
   
   cout << res;
    

    return 0;
}