#include <bits/stdc++.h>
#define rep(i, a) for (int i = 0; i < (a); i++)
#define rep2(i, a, b) for (int i = (a); i < (b); i++)
#define repr(i, a) for (int i = (a) - 1; i >= 0; i--)
#define repr2(i, a, b) for (int i = (b) - 1; i >= (a); i--)
using namespace std;
typedef long long ll;
const ll inf = 1e9;
const ll mod = 1e9 + 7;

struct UF {
	vector<int> parent, size;
	UF(int n) : parent(n), size(n, 1) {
		rep (i, n) parent[i] = i;
	}
	int root(int x) {
		if (x == parent[x]) return x;
		else return parent[x] = root(parent[x]);
	}
	void unite(int x, int y) {
		x = root(x); y = root(y);
		if (x == y) return;
		if (size[x] > size[y]) swap(x, y);
		size[x] += size[y];
		parent[y] = x;
	}
	bool same(int x, int y) {
		return root(x) == root(y);
	}
};

int N;
ll X[1000], Y[1000];

ll hypot2(ll x, ll y) {
	return x * x + y * y;
}

int main() {
	cin >> N;
	rep (i, N) cin >> X[i] >> Y[i];

	ll l = 0, r = 2e9;	

	while (r - l > 1) {
		ll m = (l + r) / 2;
		UF uf(N);

		rep (i, N) {
			rep2 (j, i + 1, N) {
				if (hypot2(X[j] - X[i], Y[j] - Y[i]) <= 100 * m * m) {
					uf.unite(i, j);	
				}
			}
		}

		if (uf.same(0, N - 1)) {
			r = m;	
		} else {
			l = m;
		}
	}

	cout << r * 10 << endl;

	return 0;
}