#include<iostream>
#include<string>

using namespace std;

#define NO -1
#define YOU 0
#define ENE 1
#define SEN 0
#define KOU 1

int main(){

	int N,K;
	int ywin=0;
	int turn=YOU;
	int winlose[10001];

	
	cin>>N>>K;
	for(int j=0;j<=N+10;j++) winlose[j]=NO;
	winlose[0]=SEN;
	for(int j=0;j<=N;j++){
		for(int k=1;k<=K;k++){
			if(j+k<=N){
				if(winlose[j]==SEN) winlose[j+k]=KOU;
				else winlose[j+k]=SEN;
			}
		}
	}
	if(winlose[N]==SEN) ywin++,turn=ENE;

	for(int i=1;i<1000;i++){
		cin>>N>>K;
		if(turn==ENE) turn=YOU;
		else ywin++,turn=ENE;
	}

	cout<<ywin<<endl;
}