// yukicoder: No.94 圏外です。(EASY)
// 2019.7.28 bal4u

#include <stdio.h>
#include <math.h>

#if 1
#define gc() getchar_unlocked()
#else
#define gc() getchar()
#endif

int in()   // 整数の入力（負数対応）
{
	int n = 0, c = gc();
	if (c == '-') {	c = gc();
		do n = 10*n + (c & 0xf), c = gc(); while (c >= '0');
		return -n;
	}
	do n = 10*n + (c & 0xf), c = gc(); while (c >= '0');
	return n;
}

#define MAX 1003

/* UNION-FIND library */
int id[MAX], size[MAX];
void init(int n) { int i; for (i = 0; i < n; i++) id[i] = i, size[i] = 1; }
int root(int i) { while (i != id[i]) id[i] = id[id[i]], i = id[i]; return i; }
int connected(int p, int q) { return root(p) == root(q); }
void unite(int p, int q) {
    int i = root(p), j = root(q); if (i == j) return;
    if (size[i] < size[j]) id[i] = j, size[j] += size[i]; else id[j] = i, size[i] += size[j];
}

int N;
int x[MAX], y[MAX];
int hi[MAX], grp[MAX][MAX];
int idx[MAX], gz = 1;

int dis(int i, int j) {
	int dx = x[i]-x[j], dy = y[i]-y[j];
	return dx*dx + dy*dy;
}

int main()
{
	int i, j, k, ans;
	
	N = in(); init(N);
	if (N == 0) { puts("1.000000000000"); return 0; }
	for (i = 0; i < N; i++) x[i] = in(), y[i] = in();
	for (i = 1; i < N; i++) for (j = 0; j < i; j++) {
		if (dis(i, j) <= 100) unite(i, j);
	}
	for (i = 0; i < N; i++) {
		j = root(i);
		if (idx[j] == 0) idx[j] = gz++;
		k = idx[j];
		grp[k][hi[k]++] = i;
	}

	ans = 0;
	for (k = 1; k < gz; k++) {
		for (i = 0; i < hi[k]; i++) for (j = i+1; j < hi[k]; j++) {
			int a = dis(grp[k][i], grp[k][j]);
			if (a > ans) ans = a;
		}
	}
	printf("%.12lf\n", sqrt(ans)+2);
	return 0;
}