codeforces 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 p_i people living in it and the room can accommodate q_i people in total (p_i ≤ q_i). 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 p_i and q_i (0 ≤ p_i ≤ q_i ≤ 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

AC:

#include<bits/stdc++.h>
using namespace std;
int main()
{
    int n;
    scanf("%d",&n);
    int p[110],q[110],cha[110];
    for(int i=0;i<n;i++)
    {
        scanf("%d%d",p+i,q+i);
        cha[i]=q[i]-p[i];
    }
    int ans=0;
    for(int i=0;i<n;i++)
        if(cha[i]>=2)
            ans++;
    printf("%d\n",ans);
}