f = open('27-8a.txt')
a = list(map(int, f.readlines()[1:]))
k = float('inf')
for i in range(len(a)-5):
    for j in range(i+5, len(a)):
        if a[i]**2 + a[j]**2 < k:
            k = a[i]**2 + a[j]**2
print(k)