import sys
import math

def find_minimum_ruler_length(points):
    max_distance = 0
    n = len(points)
    
    for i in range(n):
        for j in range(i + 1, n):
            x1, y1 = points[i]
            x2, y2 = points[j]
            distance = math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2)
            max_distance = max(max_distance, distance)
    
    return max_distance

def main():
    input = sys.stdin.read
    data = input().split()
    
    n = int(data[0])  # 点の数
    points = []
    
    index = 1
    for _ in range(n):
        x = int(data[index])
        y = int(data[index + 1])
        points.append((x, y))
        index += 2
    
    minimum_ruler_length = find_minimum_ruler_length(points)
    print(f"{minimum_ruler_length:.6f}")

if __name__ == "__main__":
    main()