import sys
from collections import Counter

# 输入
n, m = map(int, sys.stdin.readline().strip().split())
matrix = []
for _ in range(n):
    matrix.append(list(sys.stdin.readline().strip()))

# 矩阵转置
rol = []
for j in range(m):
    string = []
    for i in range(n):
        string.append(matrix[i][j])
    rol.append(''.join(string))

#统计相同的列数
rol_dict = Counter(rol)

print(max(rol_dict.values()))

真无语