#include <iostream>
#include <string>
#include <cmath>
#include<algorithm>
#include<stack>
#include<queue>
#include<map>
#include<set>
#include<iomanip>
#define _USE_MATH_DEFINES
#include <math.h>
#include <functional>
#include<complex>
using namespace std;

#define rep(i,x) for(ll i=0;i<x;i++)
#define repn(i,x) for(ll i=1;i<=x;i++)

typedef long long ll;
const ll INF = 1e17;
const ll MOD = 998244353;
const ll MAX = 4000001;
const double eps = 1E-18;

ll max(ll a, ll b) {
	if (a > b) { return a; }
	return b;
}

ll min(ll a, ll b) {
	if (a > b) { return b; }
	return a;
}

ll gcd(ll a, ll b) {
	if (b == 0) { return a; }
	if (a < b) { return gcd(b, a); }
	return gcd(b, a % b);
}

ll lcm(ll a, ll b) {
	return a / gcd(a, b) * b;
}

struct edge {
	ll ind;
	ll fr;
	ll to;
	ll d;
};

class mint {
	long long x;
public:
	mint(long long x = 0) : x((x% MOD + MOD) % MOD) {}
	mint operator-() const {
		return mint(-x);
	}
	mint& operator+=(const mint& a) {
		if ((x += a.x) >= MOD) x -= MOD;
		return *this;
	}
	mint& operator-=(const mint& a) {
		if ((x += MOD - a.x) >= MOD) x -= MOD;
		return *this;
	}
	mint& operator*=(const  mint& a) {
		(x *= a.x) %= MOD;
		return *this;
	}
	mint operator+(const mint& a) const {
		mint res(*this);
		return res += a;
	}
	mint operator-(const mint& a) const {
		mint res(*this);
		return res -= a;
	}
	mint operator*(const mint& a) const {
		mint res(*this);
		return res *= a;
	}

	mint operator^(const ll& t)const {
		if (!t) return 1;
		mint a = pow(t >> 1);
		a *= a;
		if (t & 1) a *= *this;
		return a;
	}

	mint pow(ll t) const {
		if (!t) return 1;
		mint a = pow(t >> 1);
		a *= a;
		if (t & 1) a *= *this;
		return a;
	}
	// for prime MOD
	mint inv() const {
		return pow(MOD - 2);
	}
	mint& operator/=(const mint& a) {
		return (*this) *= a.inv();
	}
	mint operator/(const mint& a) const {
		mint res(*this);
		return res /= a;
	}

	friend ostream& operator<<(ostream& os, const mint& m) {
		os << m.x;
		return os;
	}
};

///////////////////////////


int main() {
	string S, T;
	cin >> S >> T;

	ll N = S.size();
	vector<ll> A(N), B(N);
	rep(i, N) {
		A[i] = S[i] - '0';
		B[i] = T[i] - '0';
	}

	ll ans = -1;
	rep(i, N)if (B[i] == 1) { ans = INF; }

	ll b = 0;
	rep(i, N) if (A[i] !=B[i]) { b = 1; }
	if (b == 0) { ans = 0; }

	if (ans == INF) {
		vector<ll> l(N, 0), r(N, 0);
		
		rep(i, N) {
			rep(j, N) {
				ll x = (i - j + N) % N;
				if (B[x] == 1) { l[i] = j; break; }
			}
			rep(j, N) {
				ll x = (i + j) % N;
				if (B[x] == 1) { r[i] = j; break; }
			}
		}

		rep(f, 2*N) {
			vector<ll> C(N, 0);
			rep(i, N) C[i] = B[(i + f) % N];

			vector<pair<ll, ll>> p;
			rep(i, N) {
				if (A[i] != C[i]) { p.push_back({ l[i],max(r[i] - f,0) }); }
			}
			ll M = p.size();
			sort(p.begin(), p.end());

			vector<ll> rmax(M+1,0);
			for (ll i = M - 1; i >= 0; i--) {
				rmax[i] = max(rmax[i + 1], p[i].second);
			}

			ll now = rmax[0];
			rep(i, M) now = min(now, p[i].first + rmax[i + 1]);

			ans = min(ans, now*2 + f + M);
		}

		rep(f, 2*N) {
			vector<ll> C(N, 0);
			rep(i, N) C[i] = B[(i - f + 2*N) % N];

			vector<pair<ll, ll>> p;
			rep(i, N) {
				if (A[i] != C[i]) { p.push_back({ r[i],max(l[i] - f,0) }); }
			}
			ll M = p.size();
			sort(p.begin(), p.end());

			vector<ll> rmax(M + 1, 0);
			for (ll i = M - 1; i >= 0; i--) {
				rmax[i] = max(rmax[i + 1], p[i].second);
			}

			ll now = rmax[0];
			rep(i, M) now = min(now, p[i].first + rmax[i + 1]);

			ans = min(ans, now * 2 + f + M);
		}

	}

	cout << ans << endl;


	
	
	system("PAUSE");
}


Measured memory_bytes: 632