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.
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.
Print a single integer — the number of rooms where George and Alex can move in.
3 1 1 2 2 3 3
0
3 1 10 0 10 10 10
2
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#include<stdio.h>
int main()
{
int n,p,q;
scanf("%d",&n);
int sum=0;
while(n--)
{
scanf("%d%d",&p,&q);
if(q-p>=2)
sum++;
}
printf("%d\n",sum);
return 0;
}