좀 쉬웠다.

import math
N, M = list(map(int, input().split()))
lst = []
for i in range(N):
lst.append(list(map(int, input().split())))
target = float('-inf2 2')
for j in range(len(lst)):
min_val = min(lst[j])
if target < min_val:
target = min_val
print(target)