#include <iostream>
#include <set>
#include <algorithm>
#include <string.h>
using namespace std;
//堀江 aoj693 Event Hopping
long long int dp[200010][2][2];
std::set<long long int> ss[2];
 
int main() {
	long long int n,d,k1;
	cin>>n>>d>>k1;
	for(int i=0;i<n;i++){
		long long int s1,t1;
		cin>>s1>>t1;
		ss[s1-1].insert(t1);
	}
	memset(dp,-1,sizeof(dp));
	dp[0][0][0]=0;
	dp[0][1][0]=0;
	dp[0][0][1]=0;
	dp[0][1][1]=0;
	int ans=0;
	for(int i=0;i<=n;i++){
		for(int j=0;j<2;j++){
			for(int k=0;k<2;k++){
				long long int t0=dp[i][k][j];
				if(t0==-1)continue;
				long long int t1=0;
				if(j==k){
					t1=t0;
				}else{
					t1=t0+d+i*k1;
				}
				auto it=ss[k].lower_bound(t1);
				if(it==ss[k].end()){
					if(ans<i)ans=i;
				}else{
					long long int ta,tb;
					ta=dp[i+1][0][k];
					tb=dp[i+1][1][k];
					if(ta==-1 || (*it)+1<ta)dp[i+1][0][k]=(*it)+1;
					if(tb==-1 || (*it)+1<tb)dp[i+1][1][k]=(*it)+1;
				}
				//cout<<"("<<t1<<" "<<k<<","<<j<<","<<dp[i][k][j]<<")";
			}
		}
		//cout<<endl;
	}
	cout<<ans<<endl;
	return 0;
}

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1 738
1 4862
1 4236
2 1416
1 9905
1 4775
2 4574
2 439
1 3956
1 955
2 8862
2 801
2 2299
2 575