#include <iostream>
using namespace std;
#include<bits/stdc++.h>
int main(){
int n;
cin>>n;
int a[n], b[n];
for(int i=0;i<n;i++){
cin>>a[i];
}
for(int i=0;i<n;i++){
cin>>b[i];
}
int steps=0;
while(true){
int min = a[0];
for(int i =0; i<n;i++){
if(a[i]<min){min = a[i];}
}
for(int i =0;i<n;i++){
while(a[i]>min){
a[i] -= b[i];
steps++;
}
}
for(int i = 0; i<n;i++){
if(a[i]<0){cout<<-1;return 0;}
}
int bandpass = 0;
for(int i =0;i<n-1;i++){
if(a[i] == a[i+1]){
bandpass += 1;
}
}
if(bandpass == n-1) {cout<<steps; return 0;}
}
}