#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <sstream>
#include <cstdio>
#include <cstdlib>
#include <cmath>

using namespace std;

int n = 1000;

int main(){
    int count = 0;
    for(int i = 0; i < n; i += 1){
        long long N, k;
        cin >> N >> k;
        if(N%(k+1) == 1)
            count ++;
    }
    cout << count << endl;
    return 0;
}