// {{{ by shik
#include <bits/stdc++.h>
#include <unistd.h>
#pragma GCC diagnostic ignored "-Wunused-result"
#define SZ(x) ((int)(x).size())
#define ALL(x) begin(x),end(x)
#define RALL(x) rbegin(x),rend(x)
#define REP(i,n) for ( int i=0; i<int(n); i++ )
#define REP1(i,a,b) for ( int i=(a); i<=int(b); i++ )
#define MP make_pair
#define PB push_back
using namespace std;
typedef int64_t LL;
typedef pair<int,int> PII;
typedef vector<int> VI;

template<class T> void _R( T &x ) { cin>>x; }
void _R( int &x ) { scanf("%d",&x); }
void _R( int64_t &x ) { scanf("%" PRId64,&x); }
void _R( double &x ) { scanf("%lf",&x); }
void _R( char &x ) { scanf(" %c",&x); }
void _R( char *x ) { scanf("%s",x); }
void R() {}
template<class T, class... U> void R( T& head, U&... tail ) { _R(head); R(tail...); }

template<class T> void _W( const T &x ) { cout<<x; }
void _W( const int &x ) { printf("%d",x); }
void _W( const int64_t &x ) { printf("%" PRId64,x); }
void _W( const double &x ) { printf("%.16f\n",x); }
void _W( const char &x ) { putchar(x); }
void _W( const char *x ) { printf("%s",x); }
template<class T> void _W( const vector<T> &x ) { for (auto i = x.begin(); i != x.end(); _W(*i++)) if (i != x.cbegin()) putchar(' '); }
void W() {}
template<class T, class... U> void W( const T& head, const U&... tail ) { _W(head); putchar(sizeof...(tail)?' ':'\n'); W(tail...); }

template<class T> inline bool chkmax( T &a, const T &b ) { return b>a ? a=b,true : false; }
template<class T> inline bool chkmin( T &a, const T &b ) { return b<a ? a=b,true : false; }
template<class T, class F=less<T>> void sort_uniq( vector<T> &v, F f=F() ) {
    sort(begin(v),end(v),f);
    v.resize(unique(begin(v),end(v))-begin(v));
}

template<class T> using MaxHeap = priority_queue<T>;
template<class T> using MinHeap = priority_queue<T, vector<T>, greater<T>>;

#ifdef SHIK
template<class T> void _dump(const char *s, T &&head) { cerr << s << "=" << head << endl; }
template<class T, class... Args> void _dump(const char *s, T &&head, Args &&... tail) {
    for (int c = 0; *s != ',' || c != 0; cerr << *s++) {
        if (*s == '(' || *s == '[' || *s == '{') c++;
        if (*s == ')' || *s == ']' || *s == '}') c--;
    }
    cerr << "=" << head << ", ";
    _dump(s + 1, tail...);
}
#define dump(...) do { fprintf(stderr, "%s:%d - ", __PRETTY_FUNCTION__, __LINE__); _dump(#__VA_ARGS__, __VA_ARGS__); } while (0)

template<class Iter> ostream &_out(ostream &s, Iter b, Iter e) {
    s << "[";
    for (auto it = b; it != e; it++) s << (it == b ? "" : " ") << *it;
    return s << "]";
}

template<class A, class B> ostream &operator<<(ostream &s, const pair<A, B> &p) { return s << "(" << p.first << "," << p.second << ")"; }
template<class T> ostream &operator<<(ostream &s, const vector<T> &c) { return _out(s, ALL(c)); }
template<class T, size_t N> ostream &operator<<(ostream &s, const array<T, N> &c) { return _out(s, ALL(c)); }
template<class T> ostream &operator<<(ostream &s, const set<T> &c) { return _out(s, ALL(c)); }
template<class A, class B> ostream &operator<<(ostream &s, const map<A, B> &c) { return _out(s, ALL(c)); }
#else
#define dump(...)
#endif
// }}}

const int N=6010;
const int INF=1e9;

int read( int a[], int s[] ) {
    static char buf[N];
    R(buf);
    int n=strlen(buf);
    REP(i,n) a[i]=buf[i]-'0';
    REP(i,2*n) a[i+n]=a[i];
    REP(i,3*n) s[i]=a[i];
    REP(i,3*n-1) s[i+1]+=s[i];
    return n;
}

bool any( int s[], int l, int r ) {
    return s[r]-(l==0 ? 0 : s[l-1]) > 0;
}

int n,a[N],b[N],sa[N],sb[N],gl[N],gr[N];

bool spcas() {
    if ( memcmp(a,b,n*sizeof(int))==0 ) {
        W(0);
        return 1;
    }
    if ( count(b,b+n,0)==n ) {
        W(-1);
        return 1;
    }
    return 0;
}

int dp[N];
int main() {
    n=read(a,sa);
    read(b,sb);
    if ( spcas() ) return 0;
    int pre=-1;
    REP(i,3*n) {
        if ( b[i] ) pre=i;
        gl[i]=pre;
    }
    pre=-1;
    for ( int i=3*n-1; i>=0; i-- ) {
        if ( b[i] ) pre=i;
        gr[i]=pre;
    }
    // REP(i,n) dump(i+n,gl[i+n],gr[i+n]);
    int ans=INF;
    REP1(d,-n+1,n-1) {
        memset(dp,0,sizeof(dp));
        int base=0;
        REP(i,n) {
            int l=min(i+n,i+n+d);
            int r=max(i+n,i+n+d);
            if ( a[i+n]==b[i+n+d] ) continue;
            // dump(d,i);
            base++;
            if ( any(sb,l,r) ) continue;
            int dl=l-gl[i+n];
            int dr=gr[i+n]-r;
            assert(dl>=0 && dr>=0);
            chkmax(dp[dl],dr);
        }
        int mi=n;
        for ( int i=n-1; i>=0; i-- ) chkmax(dp[i],dp[i+1]);
        REP(i,n) chkmin(mi,i+dp[i+1]);
        int now=base+abs(d)+2*mi;
        // dump(now,base,d,mi);
        chkmin(ans,now);
    }
    assert(ans<INF);
    W(ans);
    return 0;
}


Measured memory_bytes: 384