#include<bits/stdc++.h>
using namespace std;
int mp[2005][2005], vis[2005][2005], dis[2005][2005];
queue< pair<int,int> > q;
int dx[4] = {0, 0, 1, -1};
int dy[4] = {1, -1, 0, 0};
vector<int> XX, YY;
int DistanceSum(int N, int *X, int *Y) {
for(int i=0; i<N; i++) {
XX.push_back(X[i]);
YY.push_back(Y[i]);
}
sort(XX.begin(), XX.end()); sort(YY.begin(), YY.end());
for(int i=0; i<N; i++) {
X[i] -= XX[0];
Y[i] -= YY[0];
}
for(int i=0; i<N; i++) {
mp[X[i]][Y[i]] = 1;
}
long long ans = 0;
for(int i=0; i<N; i++) {
for(int j=0; j<N; j++) vis[X[j]][Y[j]] = 0;
vis[X[i]][Y[i]] = 1;
q.push({X[i], Y[i]});
dis[X[i]][Y[i]] = 0;
while(!q.empty()) {
int x = q.front().first;
int y = q.front().second;
ans += dis[x][y];
q.pop();
for(int j=0; j<4; j++) {
if(mp[x+dx[j]][y+dy[j]] == 1 && vis[x+dx[j]][y+dy[j]] == 0) {
vis[x+dx[j]][y+dy[j]] = 1;
dis[x+dx[j]][y+dy[j]] = dis[x][y] + 1;
q.push({x+dx[j], y+dy[j]});
}
}
}
}
return (ans/2) % 1000000000;
}
