#include <fstream>
using namespace std;

ifstream fin("tribute.in");
ofstream fout("tribute.out");

int n,i,j,x,y,l,L,f[50001],F[50001],st[50001],dr[50001],ps[50001],pd[50001];
long long sum;

int main(){
    fin>>n>>l>>L;
    for(i=1;i<=n;i++){
        fin>>x>>y;
        f[x]++;
        F[y]++;
    }
    st[0]=0;
    ps[0]=f[0];
    for(i=1;i<=50000;i++){
        st[i]=st[i-1]+ps[i-1];
        ps[i]=ps[i-1]+f[i];
    }
    dr[50001]=0;
    pd[50001]=f[0];
    for(i=49999;i>=0;i--){
        dr[i]=dr[i+1]+pd[i+1];
        pd[i]=pd[i+1]+f[i];
    }

    for(i=0;i+l<=50000;i++){
        sol=min(sol,st[i]+dr[i+l-1]);
    }



    return 0;
}