#include <bits/stdc++.h>
using namespace std;
typedef pair<int, int> PII;
#define x first
#define y second

PII a[110];
int n, L;

vector<int> X, Y;

int ans;
int main() {
    cin >> n >> L;
    for (int i = 1; i <= n; ++i) {
        cin >> a[i].x >> a[i].y;
        X.push_back(a[i].x);
        X.push_back(a[i].x - L); // 所有可能的左上角起点坐标(x,y) 必然满足x in X,y in Y
        Y.push_back(a[i].y);
        Y.push_back(a[i].y - L);
    }

    for (int i = 0; i < X.size(); i++)
        for (int j = 0; j < Y.size(); j++) { // 枚举每个可能的左上角坐标
            int cnt = 0;
            int x = X[i], y = Y[j];
            for (int k = 1; k <= n; k++) // 枚举每个金矿
                if (a[k].x >= x && a[k].x <= x + L && a[k].y >= y && a[k].y <= y + L)
                    cnt++;

            ans = max(ans, cnt);
        }

    cout << ans << endl;

    return 0;
}