#include <algorithm>
#include <bitset>
#include <iostream>
#include <vector>
#include <map>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <string>
#include <set>

using namespace std;

namespace fastinput {
	/** Interface */

	template <class T = int> inline T readInt();
	inline double readDouble();
	inline int readUInt();
	inline int readChar();
	inline void readWord(char *s);
	inline bool readLine(char *s); // do not save '\n'
	inline bool isEof();
	inline int peekChar();
	inline bool seekEof();

	template <class T> inline void writeInt(T x, int len = -1);
	template <class T> inline void writeUInt(T x, int len = -1);
	inline void writeChar(int x);
	inline void writeWord(const char *s);
	inline void writeDouble(double x, int len = 0);
	inline void flush();

	/** Read */

	static const int buf_size = 4096;

	static char buf[buf_size];
	static int buf_len = 0, buf_pos = 0;

	inline bool isEof() {
		if (buf_pos == buf_len) {
			buf_pos = 0, buf_len = fread(buf, 1, buf_size, stdin);
			if (buf_pos == buf_len)
				return 1;
		}
		return 0;
	}

	inline int getChar() {
		return isEof() ? -1 : buf[buf_pos++];
	}

	inline int peekChar() {
		return isEof() ? -1 : buf[buf_pos];
	}

	inline bool seekEof() {
		int c;
		while ((c = peekChar()) != -1 && c <= 32)
			buf_pos++;
		return c == -1;
	}

	inline int readChar() {
		int c = getChar();
		while (c != -1 && c <= 32)
			c = getChar();
		return c;
	}

	inline int readUInt() {
		int c = readChar(), x = 0;
		while ('0' <= c && c <= '9')
			x = x * 10 + c - '0', c = getChar();
		return x;
	}

	template <class T>
	inline T readInt() {
		int s = 1, c = readChar();
		T x = 0;
		if (c == '-')
			s = -1, c = getChar();
		while ('0' <= c && c <= '9')
			x = x * 10 + c - '0', c = getChar();
		return s == 1 ? x : -x;
	}

	inline double readDouble() {
		int s = 1, c = readChar();
		double x = 0;
		if (c == '-')
			s = -1, c = getChar();
		while ('0' <= c && c <= '9')
			x = x * 10 + c - '0', c = getChar();
		if (c == '.') {
			c = getChar();
			double coef = 1;
			while ('0' <= c && c <= '9')
				x += (c - '0') * (coef *= 1e-1), c = getChar();
		}
		return s == 1 ? x : -x;
	}

	inline void readWord(char *s) {
		int c = readChar();
		while (c > 32)
			*s++ = c, c = getChar();
		*s = 0;
	}

	inline bool readLine(char *s) {
		int c = getChar();
		while (c != '\n' && c != -1)
			*s++ = c, c = getChar();
		*s = 0;
		return c != -1;
	}

	/** Write */

	static int write_buf_pos = 0;
	static char write_buf[buf_size];

	inline void writeChar(int x) {
		if (write_buf_pos == buf_size)
			fwrite(write_buf, 1, buf_size, stdout), write_buf_pos = 0;
		write_buf[write_buf_pos++] = x;
	}

	inline void flush() {
		if (write_buf_pos)
			fwrite(write_buf, 1, write_buf_pos, stdout), write_buf_pos = 0;
	}

	template <class T>
	inline void writeInt(T x, int output_len) {
		if (x < 0)
			writeChar('-'), x = -x;

		char s[24];
		int n = 0;
		while (x || !n)
			s[n++] = '0' + x % 10, x /= 10;
		while (n < output_len)
			s[n++] = '0';
		while (n--)
			writeChar(s[n]);
	}

	template <class T>
	inline void writeUInt(T x, int output_len) {
		char s[24];
		int n = 0;
		while (x || !n)
			s[n++] = '0' + x % 10, x /= 10;
		while (n < output_len)
			s[n++] = '0';
		while (n--)
			writeChar(s[n]);
	}

	inline void writeWord(const char *s) {
		while (*s)
			writeChar(*s++);
	}

	inline void writeDouble(double x, int output_len) {
		if (x < 0)
			writeChar('-'), x = -x;
		int t = (int)x;
		writeUInt(t), x -= t;
		writeChar('.');
		for (int i = output_len - 1; i > 0; i--) {
			x *= 10;
			t = std::min(9, (int)x);
			writeChar('0' + t), x -= t;
		}
		x *= 10;
		t = std::min(9, (int)(x + 0.5));
		writeChar('0' + t);
	}
}

using namespace fastinput;

int n;

int calc(int x) {
	return x % n + n;
}

int fromto(int a, int b) {
	return min(abs(a - b), n - abs(a - b));
}

int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	string a, b;
	cin >> a >> b;
	vector <int> ida, idb;
	n = a.length();
	for (int i = 0; i < n; ++i) {
		if (a[i] == '1')
			ida.push_back(i);
		if (b[i] == '1')
			idb.push_back(i);
	}
	if (idb.empty() && !ida.empty()) {
		cout << -1 << endl;
		return 0;
	}
	vector <int> keepa = ida;
	vector <int> keepb = idb;
	for (auto x : idb)
		keepb.push_back(x + n);
	for (auto x : idb)
		keepb.push_back(x + 2 * n);

	int res = 1e9;
	for (int shift = 0; shift < n; ++shift) {
		ida.clear();
		for (int one : keepa) 
			ida.push_back(calc(one + shift));
		sort(ida.begin(), ida.end());
		vector <pair <int, int> > lr;
		int cnt1 = 0;
		vector <int> ida2;
		for (auto x : ida) {
			auto itr = upper_bound(keepb.begin(), keepb.end(), x);
			auto itl = itr - 1;
			int l = x - *itl;
			int r = *itr - x;
			if (l == 0)
				++cnt1;
			else {
				ida2.push_back((x - shift) % n + n);
			}
		}
		for (auto x: ida2) {
			auto itr = upper_bound(keepb.begin(), keepb.end(), x);
			auto itl = itr - 1;
			int l = x - *itl;
			int r = *itr - x;
			lr.push_back({l, r});
		}
		sort(lr.begin(), lr.end());
		vector <int> suff;
		vector <int> pref;
		suff.push_back(0);
		pref.push_back(0); 
		for (auto it = lr.begin(); it != lr.end(); ++it)
			pref.push_back(max(it->first, pref.back()));
		for (auto it = lr.rbegin(); it != lr.rend(); ++it)
			suff.push_back(max(it->second, suff.back()));
		reverse(suff.begin(), suff.end());

		for (int i = 0; i < pref.size(); ++i) {
			int ls = pref[i];
			int rs = suff[i];

			res = min(res, 
				(int)idb.size() - cnt1 + 2 * ls + rs + fromto(rs, shift) + (int)ida2.size()
				);
			res = min(res,
				(int)idb.size() - cnt1 + ls + 2 * rs + fromto(n - ls, shift) + (int)ida2.size()
			);
		}

	}
	cout << res << endl;
	return 0;
}

Measured memory_bytes: 384