import std.algorithm, std.array, std.container, std.range, std.bitmanip; import std.numeric, std.math, std.bigint, std.random, core.bitop; import std.string, std.conv, std.stdio, std.typecons; struct point { int x, y; point opBinary(string op)(point rhs) { static if (op == "+") return point(x + rhs.x, y + rhs.y); else static if (op == "-") return point(x - rhs.x, y - rhs.y); } int abs2() { return x ^^ 2 + y ^^ 2; } } class UnionFind { int[] par; this(int n) { par = new int[](n); par[] = -1; } int find(int i) { if (par[i] < 0) { return i; } else { par[i] = find(par[i]); return par[i]; } } void unite(int i, int j) { auto pi = find(i), pj = find(j); if (pi != pj) par[j] = pi; } } void main() { auto n = readln.chomp.to!int; auto pi = iota(n) .map!(_ => readln.split.map!(to!int)) .map!(rd => point(rd[0], rd[1])).array; auto uf = new UnionFind(n); foreach (i; 0..n - 1) foreach (j; i..n) if ((pi[i] - pi[j]).abs2 <= 100) uf.unite(i, j); int[][int] h; foreach (i; 0..n) h[uf.find(i)] ~= i; auto maxDist = 0; foreach (qi; h.byValue) foreach (i; 0..qi.length - 1) foreach (j; i + 1..qi.length) maxDist = max(maxDist, (pi[qi[i]] - pi[qi[j]]).abs2); writefln("%f", n == 0 ? 1 : maxDist.to!real.sqrt + 2); }