n, m = map(int,input().split())
tatal_max = 1

arr=[]
for i in range(0,n):
    arr.append(str(input()))
columns = {}
for j in range(m):
    col = ''.join([arr[i][j] for i in range(n)])
    if col in columns:
        columns[col] += 1
    else:
        columns[col] = 1

tatal_max = max(columns.values())
print(tatal_max)

就是找相同的列