SOURCE

const map = [
  ['','','','','','','',''],
  ['','','@','','','','@',''],
  ['','','','','@','','',''],
  ['@','','@','','','@','',''],
  ['','','@','','','','',''],
  ['','','','@','@','','@',''],
  ['','@','','','','@','',''],
  ['','','','','','','','']
]

function countPath (map) {
  let n = map.length - 1
  let m = map[0].length - 1
  let opt = Array.from({length:n}, _=> Array.from({length:m}, _ => 0))
  console.log(opt)
  
// 	for (let i = n - 1; i >= 0; i--) {
//     for (let j = m - 1; j >=0; j--) {
      
//     }
//   }
//   opt[i][j] = opt[i+1][j] + opt[i][j+1]
}