#include <iostream>
#include <algorithm>
#include<cmath>
#include<cstring>
#include<cstdio>
#include<cstdlib>
#include<vector>
#include<iomanip>
#include<ctime>
#include<set>
#include<map>
#include<queue>
#include<stack>
#define sqr(x) ((x)*(x))
#define fz1(i,n) for ((i)=1;(i)<=(n);(i)++)
#define fd1(i,n) for ((i)=(n);(i)>=1;(i)--)
#define fz0g(i,n) for ((i)=0;(i)<=(n);(i)++)
#define fd0g(i,n) for ((i)=(n);(i)>=0;(i)--)
#define fz0k(i,n) for ((i)=0;(i)<(n);(i)++)
#define fd0k(i,n) for ((i)=(long long)((n)-1);(i)>=0;(i)--)
#define fz(i,x,y) for ((i)=(x);(i)<=(y);(i)++)
#define fd(i,y,x) for ((i)=(y);(i)>=(x);(i)--)
#define fzin fz1(i,n)
#define fzim fz1(i,m)
#define fzjn fz1(j,n)
#define fzjm fz1(j,m)
#define ff(c,itr) for (__typeof((c).begin()) itr=(c).begin();itr!=(c).end();itr++)
#define rdst(st,len){static char ss[len];scanf(" %s",ss);(st)=ss;}
//#define T_ int
using namespace std;
//struct bit{T_ arr[1000005];int lowbit(int x){return x&(-x);}void add(int x,T_ y){for (int i=x;i<=n;i+=lowbit(i)) arr[i]+=y;}T_ query(int x){T_ s=0;for (int i=x;i>0;i-=lowbit(i)) s+=arr[i];return s;}};
//struct seg{struct treedot{int l,r;T_ sum,add;void update(T_ x){sum+=(r-l+1)*x; add+=x;}}c[800005];void pushdown(int id){if (c[id].add){c[id*2].update(c[id].add);c[id*2+1].update(c[id].add);c[id].add=0;}}void pushup(int id){c[id].sum=c[id*2].sum+c[id*2+1].sum;}void build(int id,int l,int r){if (l>r) return;c[id].l=l;c[id].r=r;c[id].sum=0;c[id].add=0;if (l==r) c[id].sum=0;else{int mid=l+(r-l)/2;build(id*2,l,mid);build(id*2+1,mid+1,r);pushup(id);}}void update(int id,int le,int ri,T_ x){if (le>c[id].r||ri<c[id].l) return;if (le<=c[id].l&&c[id].r<=ri) c[id].update(x);else{pushdown(id);update(id*2,le,ri,x);update(id*2+1,le,ri,x);pushup(id);}}T_ query(int id,int le,int ri){if (ri<c[id].l||c[id].r<le) return 0;if (le<=c[id].l&&c[id].r<=ri) return c[id].sum;T_ ans=0;pushdown(id);ans+=query(id*2,le,ri);ans+=query(id*2+1,le,ri);pushup(id);return ans;}};
//struct bit_2d{T_ a[2005][2005];int lowbit(int x){return x&(-x);}void add(int x,int y,T_ z){int i,j;for (i=x;i<=2000;i+=lowbit(i)){for (j=y;j<=2000;j+=lowbit(j)){a[i][j]+=z;}}}T_ query(int x,int y){int i,j;T_ s=0;for (i=x;i;i-=lowbit(i)){for (j=y;j;j-=lowbit(j)){s+=a[i][j];}}return s;}T_ query(int x,int y,int xx,int yy){return query(xx,yy)-query(x-1,yy)-query(xx,y-1)+query(x-1,y-1);}};
int n,m,i,j,l[2005],r[2005],s1,s2,s3,ans;
string a,b;
int main()
{
	cin>>a>>b;
	n=a.length();
	bool f=1;
	fz0k(i,n) if (b[i]=='1') f=0;
	if (f)
	{
		if (a!=b)
		{
			puts("-1");
			return 0;
		}
	}
	fz0k(i,n)
	{
		j=i;
		while (b[j]=='0')
		{
			j=(j+1)%n;
			r[i]++;
			if (r[i]==n)
			{
				r[i]=n*18;
				break;
			}
		}
		j=i;
		while (b[j]=='0')
		{
			j=(j+n-1)%n;
			l[i]++;
			if (l[i]==n)
			{
				l[i]=n*18;
				break;
			}
		}
	}
	ans=n*18;
	fz0k(i,n)
	{
		s1=i;s3=0;
		vector<pair<int,int> > v;v.clear();
		fz0k(j,n)
		{
			if (a[j]!=b[(j+n-i)%n])
			{
				s3++;
				if (l[j]>i)
				{
					v.push_back(make_pair(l[j]-i,r[j]));
				}
			}
		}
		sort(v.begin(),v.end());
		reverse(v.begin(),v.end());
		s2=n*18;
		int s=0;
		ff(v,it)
		{
			s2=min(s2,it->first*2+s);
			s=max(s,it->second*2);
		}
		s2=min(s2,s);
		ans=min(ans,s1+s2+s3);
	}
	fz0k(i,n)
	{
		s1=i;s3=0;
		vector<pair<int,int> > v;v.clear();
		fz0k(j,n)
		{
			if (a[j]!=b[(j+i)%n])
			{
				s3++;
				if (r[j]>i)
				{
					v.push_back(make_pair(r[j]-i,l[j]));
				}
			}
		}
		sort(v.begin(),v.end());
		reverse(v.begin(),v.end());
		s2=n*18;
		int s=0;
		ff(v,it)
		{
			s2=min(s2,it->first*2+s);
			s=max(s,it->second*2);
		}
		s2=min(s2,s);
		ans=min(ans,s1+s2+s3);
	}
	if (ans==n*18) puts("-1"); else cout<<ans<<endl;
	return 0;
}

Measured memory_bytes: 384