#include<bits/stdc++.h>
#define inf 0x3f3f3f3f
#define ll long long
#define maxn 300005
using namespace std;
int n,maxx;
int vis[maxn];
struct nod{
	int id[2],val;
}x[maxn],y[maxn],ans[10];
int cmp(nod x,nod y){return x.val>y.val;}
int main()
{
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>x[i].val>>y[i].val;	
		x[i].id[0]=y[i].id[0]=i;	
	}
 
	int m1,m2;
	sort(x+1,x+1+n,cmp);
	sort(y+1,y+1+n,cmp);
	ans[1].val=x[1].val-x[n].val,ans[1].id[0]=x[1].id[0],ans[1].id[1]=x[n].id[0];
	ans[2].val=y[1].val-y[n].val,ans[2].id[0]=y[1].id[0],ans[2].id[1]=y[n].id[0];
	ans[3].val=x[2].val-x[n].val,ans[3].id[0]=x[2].id[0],ans[3].id[1]=x[n].id[0];
	ans[4].val=x[1].val-x[n-1].val,ans[4].id[0]=x[1].id[0],ans[4].id[1]=x[n-1].id[0];
	ans[5].val=y[2].val-y[n].val,ans[5].id[0]=y[2].id[0],ans[5].id[1]=y[n].id[0];
	ans[6].val=y[1].val-y[n-1].val,ans[6].id[0]=y[1].id[0],ans[6].id[1]=y[n-1].id[0];
    
    int id1,id2;
	sort(ans+1,ans+1+10,cmp);
	for(int i=1;i<=10;i++)
	{
		if(i==1)
		{
			id1=ans[1].id[0],id2=ans[1].id[1];
		}
		if(ans[i].id[0]==id1&&ans[i].id[1]==id2)continue;
		if(ans[i].id[1]==id1&&ans[i].id[0]==id2)continue;
		cout<<ans[i].val;
		break;
	}
}
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define P pair<int, int>
#define fi first
#define se second
#define rep(i, n) for (int i = 0; i < n; i++)
#define all(v) v.begin(), v.end()
#define pb push_back
template <class T, class U>
inline bool chmax(T &a, U b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}
template <class T, class U>
inline bool chmin(T &a, U b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}
constexpr int INF = 1000000000;
constexpr ll llINF = 1000000000000000000;
constexpr int mod = 1000000007;
constexpr double eps = 1e-10;
const double pi = acos(-1);
int dx[] = {0, 1, 0, -1}, dy[] = {1, 0, -1, 0};
int Random(int mi, int ma) {
    random_device rnd;
    mt19937 mt(rnd());  // 32bit
    //[mi,ma]
    uniform_int_distribution<int> engine(mi, ma);
    return engine(mt);
}
/*
vector<vector<ll>>C,sC;
void init_comb(int n,int m){
    C.resize(n+1,vector<ll>(m+1,0));
    sC.resize(n+1,vector<ll>(m+1,0));
    C[0][0]=1;
    for(int i=1;i<=n;i++){
        C[i][0]=1;
        for(int j=1;j<=m;j++){
            C[i][j]=(C[i-1][j-1]+C[i-1][j])%mod;
        }
    }
    rep(i,n+1){
        rep(j,m){
            sC[i][j+1]=(sC[i][j]+C[i][j])%mod;
        }
    }
}*/
bool prime(int a) {
    if (a == 1) return false;
    for (int i = 2; i * i <= a; i++) {
        if (a % i == 0) return false;
    }
    return true;
}
vector<int> primes;
void init_prime(int n) {
    primes.push_back(2);
    for (int i = 3; i <= n; i += 2) {
        bool f = true;
        for (int j : primes) {
            if (j * j > i) break;
            if (i % j == 0) {
                f = false;
                break;
            }
        }
        if (f) primes.push_back(i);
    }
}
ll modpow(ll a, ll b) {
    ll res = 1;
    while (b) {
        if (b & 1) {
            res *= a;
            res %= mod;
        }
        a *= a;
        a %= mod;
        b >>= 1;
    }
    return res;
}
vector<ll> inv, fact, factinv;
void init_fact(int n) {
    inv.resize(n + 1);
    fact.resize(n + 1);
    factinv.resize(n + 1);
    inv[0] = 0;
    inv[1] = 1;
    fact[0] = 1;
    factinv[0] = 1;
    for (ll i = 1; i <= n; i++) {
        if (i >= 2) inv[i] = mod - ((mod / i) * inv[mod % i] % mod);
        fact[i] = (fact[i - 1] * i) % mod;
        factinv[i] = factinv[i - 1] * inv[i] % mod;
    }
}
ll _inv(ll a, ll m = mod) {
    // gcd(a,m) must be 1
    ll b = m, u = 1, v = 0;
    while (b) {
        ll t = a / b;
        a -= t * b;
        swap(a, b);
        u -= t * v;
        swap(u, v);
    }
    u %= m;
    if (u < 0) u += m;
    return u;
}
ll comb(int a, int b) {
    if (a < b) return 0;
    if (a < 0) return 0;
    return fact[a] * factinv[a - b] % mod * factinv[b] % mod;
}
ll multicomb(int a, int b) { return comb(a + b - 1, b); }
void solve() {
    int n;
    cin >> n;
    string s, t;

    cin >> s >> t;
    if (count(all(s), '1') != count(all(t), '1')) {
        cout << "-1" << endl;
        return;
    }
    int cnt = count(all(s), '0');
    int r = cnt, a = 0;
    rep(i, s.size()) {
        if (s[i] == '0') {
            if (t[i] == '0') {
                if (a == 0) r--;
            } else {
                a++;
            }
        } else if (t[i] == '0') {
            a--;
        }
    }
    cout << r << endl;
}
int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    // int t;cin>>t;while(t--)
    solve();
    return 0;
}