18.py

coords = set()
connects = {}
for _ in range(int(input())):
    new_coord = tuple(input().split())
    coords.add(new_coord)

for coord in coords:
    for new_coord in coords:
        if new_coord[0][:-1] == coord[0][:-1] and new_coord[1][:-1] == coord[1][:-1]:
            connects[coord] = connects.get(coord, 0) + 1


print(max(connects.values()))