https://www.acmicpc.net/problem/14656
const fs=require('fs') ip=fs.readFileSync(0).toString().split('\n') n=parseInt(ip[0]) count=0 v=ip[1].split(' ').map(Number) for(i=0;i<n;i++){ a=parseInt(v[i]) if(a!=i+1) count++ } console.log(count)