lines = []

with open("input") as f:
    for line in f:
        lines.append(line.strip())

antennas: dict[str, list[tuple[int, int]]] = {}
for row_idx, line in enumerate(lines):
    for col_idx, char in enumerate(line):
        if char != ".":
            if char not in antennas:
                antennas[char] = []

            antennas[char].append((row_idx, col_idx))

row_count = len(lines)
col_count = len(lines[0])
antinodes: set[tuple[int, int]] = set()
for antenna_list in antennas.values():
    for idx, antenna1 in enumerate(antenna_list):
        for antenna2 in antenna_list[idx + 1:]:
            row_diff = antenna2[0] - antenna1[0]
            col_diff = antenna2[1] - antenna1[1]

            pos1 = (antenna1[0] - row_diff, antenna1[1] - col_diff)
            pos2 = (antenna2[0] + row_diff, antenna2[1] + col_diff)

            if 0 <= pos1[0] < row_count and 0 <= pos1[1] < col_count:
                antinodes.add(pos1)

            if 0 <= pos2[0] < row_count and 0 <= pos2[1] < col_count:
                antinodes.add(pos2)

print(len(antinodes))