import sys
from collections import Counter

n, m = map(int, sys.stdin.readline().split())
matrix = [sys.stdin.readline().strip() for _ in range(n)]
columns = []
for j in range(m):
    col = ''.join([matrix[i][j] for i in range(n)])
    columns.append(col)
count = Counter(columns)
print(max(count.values()))