C++ :

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>

using namespace std;
int n,m,c; 
int a[1010],b[1010];
int main(){
	cin>>m>>n>>c;
	for(int i=1;i<=m;i++){
		cin>>a[i];
	}
	for(int j=1;j<=n;j++){
		cin>>b[j];
	}
	sort(a+1,a+1+m);
	sort(b+1,b+1+n);
	int num=0,j=1;
	for(int i=1;i<=min(n,m);++i){
		if(a[i]+c<b[j])continue;
		while(abs(b[j]-a[i])>c&&j<=n)j++;
		//cout<<a[i]<<' '<<b[j];
		if(j>n)break;
		j++;
		num++;
	}
	cout<<num;
	return 0;
}