t=int(input())
c=0
while(t>0):
p,q=map(int,input().split())
if(q-p>=2):
c+=1
t-=1
print(c)#include<iostream>
#include<bits/stdc++.h>
using namespace std;
int main(){
long long n;
cin>>n;
long long x,y;
long long cnt=0;
for(int i=0;i<n;i++){
cin>>x>>y;
if(y-x>=2){
cnt++;
}
}
cout<<cnt<<endl;
return 0;
}977. Squares of a Sorted Array | 852. Peak Index in a Mountain Array |
461. Hamming Distance | 1748. Sum of Unique Elements |
897. Increasing Order Search Tree | 905. Sort Array By Parity |
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1450. Number of Students Doing Homework at a Given Time | 700. Search in a Binary Search Tree |
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1299. Replace Elements with Greatest Element on Right Side | 1768. Merge Strings Alternately |
561. Array Partition I | 1374. Generate a String With Characters That Have Odd Counts |
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1323. Maximum 69 Number | 832. Flipping an Image |
1295. Find Numbers with Even Number of Digits | 1704. Determine if String Halves Are Alike |
1732. Find the Highest Altitude | 709. To Lower Case |
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1588. Sum of All Odd Length Subarrays | 1662. Check If Two String Arrays are Equivalent |
1832. Check if the Sentence Is Pangram | 1678. Goal Parser Interpretation |