N = int(input())
A = list(input())

A.sort()
if len(A) % 2 == 0 :
    Y = (A[len(A)/2 - 0.5] + A[len(A)/2 + 0.5])/2
else:
    Y = A[len(A)/2 + 0.5]
print(f"{Y:.1f}")