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 PriorityQueue=(function(){
  function f(){return new PriorityQueue();}
  function PriorityQueue(){
    this.heap=[];
  }
  PriorityQueue.prototype.push=function(x){
    var h=this.heap,i=h.length++,j;
    while(i){
      j=i-1>>1;
      if(h[j][0]<=x[0])break;
      h[i]=h[j],i=j;
    }
    h[i]=x;
  };
  PriorityQueue.prototype.pop=function(){
    var h=this.heap,r=h[0],x=h.pop(),l=h.length,i=0,j;
    if(l===0)return r;
    var k=l>>1;l--;
    while(i<k){
      j=(i<<1)+1;
      if(j<l&&h[j+1][0]<h[j][0])j++;
      if(x[0]<=h[j][0])break;
      h[i]=h[j],i=j;
    }
    h[i]=x;
    return r;
  };
  return f;
})();

console.log(main());
function main(){
  var n = o.a();
  var a = o.l();
  var b = o.l();
  var pq = PriorityQueue();
  for(var i = 0; i < n; i++){
    if(a[i] === b[i])continue;
    if(a[i] > b[i])return -1;
    pq.push([-b[i],i]);
  }
  var ans = 0;
  while(pq.heap.length){
    var t = pq.pop();
    var j = t[1], x = -t[0];
    var y = b[(j+n-1)%n] + b[(j+1)%n];
    var z = b[j]/y|0;
    if(z === 0)return -1;
    ans += z;
    b[j] %= y;
    if(a[j] === b[j])continue;
    if(a[j] > b[j])return -1;
    pq.push([-b[j],j]);
  }
  return ans;
}