import * as fs from "fs"

const t0 = process.hrtime.bigint()

const raw = fs.readFileSync("input.txt","utf8").split(/\r?\n/)
const h = raw.length

const rows: Uint8Array[] = new Array(h)
const lens = new Int32Array(h)

for (let i = 0; i < h; i++) {
  const s = raw[i]
  if (!s) {
    rows[i] = new Uint8Array(0)
    lens[i] = -1
  } else {
    const a = new Uint8Array(s.length)
    for (let j = 0; j < s.length; j++) a[j] = s.charCodeAt(j)
    rows[i] = a
    lens[i] = s.length
  }
}

const adj = new Int8Array([
   0,-1,  0,1,  -1,0,  1,0,
  -1,-1, -1,1,  1,-1, 1,1
])

let maxw = 0
for (let i = 0; i < h; i++) if (lens[i] > maxw) maxw = lens[i]
const neigh = Array.from({length:h},()=>new Int8Array(maxw))

for (let r = 0; r < h; r++) {
  const w = lens[r]
  if (w < 0) continue
  const row = rows[r]
  for (let c = 0; c < w; c++) {
    if (row[c] !== 64) continue
    for (let k = 0; k < 16; k += 2) {
      const rr = r + adj[k]
      if (rr < 0 || rr >= h) continue
      const w2 = lens[rr]
      if (w2 < 0) continue
      const cc = c + adj[k+1]
      if (cc < 0 || cc >= w2) continue
      neigh[rr][cc]++
    }
  }
}

let removed = 0
const buf_r: number[] = []
const buf_c: number[] = []

while (true) {
  buf_r.length = 0
  buf_c.length = 0

  for (let r = 0; r < h; r++) {
    const w = lens[r]
    if (w < 0) continue
    const row = rows[r]
    const nr = neigh[r]
    for (let c = 0; c < w; c++) {
      if (row[c] === 64 && nr[c] < 4) {
        buf_r.push(r)
        buf_c.push(c)
      }
    }
  }

  const n = buf_r.length
  if (n === 0) break
  removed += n

  for (let i = 0; i < n; i++) {
    const r = buf_r[i]
    const c = buf_c[i]
    rows[r][c] = 46
    for (let k = 0; k < 16; k += 2) {
      const rr = r + adj[k]
      if (rr < 0 || rr >= h) continue
      const w2 = lens[rr]
      if (w2 < 0) continue
      const cc = c + adj[k+1]
      if (cc < 0 || cc >= w2) continue
      neigh[rr][cc]--
    }
  }
}

const t1 = process.hrtime.bigint()
console.log(removed)
console.log(`Time: ${Number(t1 - t0)/1e6} ms`)