#include <iostream>

using namespace std;

int main(){
    int T = 1000;
    int won = 0;
    int first = 0;
    for(int t = 0; t < T; t++){
        int n, k;
        cin >> n >> k;
        if(n % (k+1) == 0){
            won += first;
        }else{
            won += 1 - first;
            first = 1 - first;
        }
    }
    cout << won << endl;
    return 0;
}