The input is a natural number n — the number of rows and columns in the square matrix. Next, the elements of the matrix are entered line by line with a space. Output the maximum element located on the main diagonal and below the main diagonal

# 1 2 3
# 4 5 6
# 7 8 9

def add(a, b):
  return a + b

def max_el(a):
  if n == 1:
    return a[0][0]
  if n == 2:
    return max(a[0][0], a[1][0], a[1][1])
  res = a[0][0]
  for i in range(len(a)):
    for j in range(len(a[i])):
      if i == j:
        if a[i][j] > res:
          res = a[i][j]
      if i > j:
        if a[i][j] > res:
          res = a[i][j]
  return res

n = int(input())
a = []
for i in range(n):
  a.append(list(map(int, input().split())))
print(max_el(a))