let fs = require('fs')

function step(c) {
  let st = state
  let {s, q, x, y} = st
  if (c=='[' || c==']') {
      st.s = s^1
      st.q = 0
  }
  else if (q == 1) {
    if (x == c) {
      st.q = 1
    }
    else {
      st.q = 2
      st.x = c
    }
  }
  else if (q == 2) {
    if (y == c) {
      st.q = 3
    }
    else {
      st.q = 2
      st.x = y
      st.y = c
    }
  }
  else if (x == c) {
    st.s = s & 1 ? 4 : 2
    st.q = 2
    st.x = y
    st.y = c
  }
  else if (q == 0 || y == c) {
    st.q = 1
    st.x = c
  }
  else {
    st.q = 2
    st.x = y
    st.y = c
  }
}

let state = {q: 0, s: 0, x: 0, y: 0}
console.log(fs.readFileSync('./data/7.txt').toString().trim().split('\n')
  .reduce((count, ip) => {
    let s = state
    s.q = s.s = s.x = s.y = 0
    let i = 0, c = ip.length
    while (i < c && (s.s & 4) == 0) {
      step(ip[i])
      i++
    }
    return count + ((s.s >> 1) == 1)
  }, 0))