"use strict";
var GET=(function(){function f(s){return new g(s);}function g(s){this._s=s.trim().split("\n");this._y=0;}g.prototype.a=function(f){var s=this._s, y=this._y, r;if(typeof s[y]==="string")s[y]=s[y].split(" ").reverse();r=s[y].pop();if(!s[y].length)this._y++;return f?r:+r;};g.prototype.l=function(f){var s=this._s[this._y++].split(" ");return f?s:s.map(a=>+a);};g.prototype.m=function(n,f){var r=this._s.slice(this._y,this._y+=n).map(a=>a.split(" "));return f?r:r.map(a=>a.map(a=>+a));};g.prototype.r=function(n,f){var r=this._s.slice(this._y,this._y+=n);return f?r:r.map(a=>+a);};return f;})();
var o=GET(require("fs").readFileSync("/dev/stdin","utf8"));
function xArray(v){var a=arguments,l=a.length,r="Array(a["+--l+"]).fill(0).map(x=>{return "+v+";})";while(--l)r="Array(a["+l+"]).fill(0).map(x=>"+r+")";return eval(r);}

var myOut = main();
if(myOut !== undefined)console.log(myOut);
function main(){
  var n = o.a();
  var a = o.l();
  var b = o.l();
  var INF = 1e9;
  var c = xArray(0,n,n+1);
  for(var i = 0; i < n; i++){
    for(var j = 0; j < n; j++){
      if((i+j)&1){
        c[i][j+1] = b[i];
      }else{
        c[i][j+1] = a[i];
      }
    }
  }
  var m = 1 << n;
  var dp = xArray(INF,m,n);
  for(var i = 1; i < m; i++){
    var bc = 0, x = i, bj = -1;
    while(x){
      if(x&1)bc++;
      bj++;
      x>>=1;
    }
    if(bc > 1){for(var j = 0; j < n; j++){
      if((i & (1<<j)) === 0)continue;
      bj = j;
      var bit = 0;
      for(var k = n; k--;){
        if(j === k){bit++;continue;}
        var bk = 1<<k;
        if((i & bk) === 0)continue;
        var bx = i^bk;
        if(dp[i][k] > dp[bx][j]+bit && c[j][bc-1] <= c[k][bc])dp[i][k] = dp[bx][j]+bit;
        bit++;
      }
    }}else dp[i][bj] = 0;
  }
  var ans = Math.min(...dp[m-1]);
  return ans === INF ? -1 : ans;
}