#include<bits/stdc++.h>
#define sqr(x) ((x)*(x))
#define ll long long
#define ull unsigned long long
#define ui unsigned int
#define ld long double
#define vi vector<int>
#define HEAP(...) priority_queue<__VA_ARGS__ >
#define heap(...) priority_queue<__VA_ARGS__,vector<__VA_ARGS__ >,greater<__VA_ARGS__ > > 
#define pii pair<int,int> 
#define pb push_back
#define mp make_pair
#define debuge cerr<<"isok"<<endl
#define debug(x) cerr<<#x<<"="<<x<<endl
#define dprintf(...) fprintf(stderr,__VA_ARGS__)
#define SS second
#define FF first
#define ls (k<<1)
#define rs (k<<1|1)
#define clr(a,x) memset(a,x,sizeof(a))
#define cpy(a,x) memcpy(a,x,sizeof(a))
#define file(x) freopen(x".in","r",stdin),freopen(x".out","w",stdout)
#define SZ(x) ((int)x.size())
using namespace std;
template<class T> inline void gmin(T &x,const T &y){if(x>y) x=y;}
template<class T> inline void gmax(T &x,const T &y){if(x<y) x=y;}
const int BufferSize=1<<16;
char buffer[BufferSize],*Bufferhead,*Buffertail;
bool Terminal;
inline char Getchar(){
	if(Bufferhead==Buffertail){
		int l=fread(buffer,1,BufferSize,stdin);
		if(!l){Terminal=1;return 0;}
		Buffertail=(Bufferhead=buffer)+l;
	}
	return *Bufferhead++;
}
template<class T>inline bool read(T &x){
	x=0;char c=Getchar(),rev=0;
	while(c<'0'||c>'9'){c=Getchar();rev|=c=='-';if(Terminal)return 0;}
	while(c>='0'&&c<='9') x=x*10+c-'0',c=Getchar();
	if(c=='.'){
		c=Getchar();double t=0.1;
		while(c>='0'&&c<='9') x=x+(c-'0')*t,c=Getchar(),t=t/10;
	}
	x=rev?-x:x;
	return 1;
}
inline bool reads(char *x){
	char c=Getchar();
	while(c<33||c>126){c=Getchar();if(Terminal)return 0;}
	while(c>=33&&c<=126) (*x++)=c,c=Getchar();
	*x=0;return 1;
}
template<class T>inline void print(T x,const char c='\n'){
	if(!x){putchar('0');putchar(c);return;}
	if(x<0) putchar('-'),x=-x;
	int m=0,a[20];
	while(x) a[m++]=x%10,x/=10;
	while(m--) putchar(a[m]+'0');
	putchar(c);
}
//--------------------------------head---------------------------------------------

const int inf=0x3f3f3f3f;
const int N=3005,M=100005,mod=1e9+7;
template<class T,class S> inline void ch(T &x,const S y){x=(x+y)%mod;}
inline int exp(int x,int y,const int mod=::mod){
	int ans=1;
	while(y){
		if(y&1) ans=(ll)ans*x%mod;
		x=(ll)x*x%mod;y>>=1;
	}return ans;
}

struct node{int x,y;}p[N],q[N];
char str[N];
int n,a[N],b[N],pl[N],mi[N],l[N],r[N],ans=inf;
bool vis[N];
void make(int *a){
	scanf("%s",str);n=strlen(str);
	for(int i=0;i<n;i++) a[i]=str[i]-'0';
}
bool cmp(node a,node b){return a.x<b.x;}
int solve(int flag=0){
	if(flag){
		for(int j=0;j<n;j++)
			dprintf("%d %d\n",l[j],r[j]);
	}
	clr(vis,0);
	int a1=0,a2=0,ans=inf;
	for(int i=0;i<n;i++){
		p[i]=(node){l[i],i},q[i]=(node){r[i],i};
		gmax(a1,l[i]);gmax(a2,r[i]);
	}
	ans=min(a1,a2);
	sort(p,p+n,cmp);
	sort(q,q+n,cmp);
	reverse(q,q+n);q[n].x=0;
	for(int i=0,j=0;i<n;i++){
		vis[p[i].y]=1;
		while(j<n&&vis[q[j].y]) j++;
		gmin(ans,p[i].x+q[j].x);
	}
	return ans;
}

int main(){
#ifdef rqgao2014
	freopen("input.txt","r",stdin);
#endif
	make(a);make(b);
//	for(int i=0;i<n;i++) dprintf("%d ",a[i]);dprintf("\n");
//	for(int i=0;i<n;i++) dprintf("%d ",b[i]);dprintf("\n");
	bool isok=0;
	for(int i=0;i<n;i++)
		if(b[i]) isok=1;
	if(!isok){
		for(int i=0;i<n;i++)
			if(a[i]!=b[i]){puts("-1");return 0;}
		puts("0");
		return 0;
	}
	for(int i=0;i<n;i++){
		int j=i;pl[i]=mi[i]=0;
		while(!b[j]) j=(j+1)%n,pl[i]++;
		j=i;
		while(!b[j]) j=(j+n-1)%n,mi[i]++;
	}
	for(int i=0;i<n;i++){
		int cnt=0,mx=0;
		clr(l,0);clr(r,0);
		for(int j=0;j<n;j++)
			if(a[j]!=b[(j+i)%n]){
				cnt++;
				l[j]=max(pl[j]-i,0);
				r[j]=max(mi[j],0);
			}
//		if(!cnt) debug(i);
		gmin(ans,cnt+i+solve()*2);
	}
	for(int i=0;i<n;i++){
		int cnt=0,mx=0;
		clr(l,0);clr(r,0);
		for(int j=0;j<n;j++)
			if(a[j]!=b[(j+n-i)%n]){
				cnt++;
				l[j]=max(mi[j]-i,0);
				r[j]=max(pl[j],0);
			}
		if(i==1) debug(cnt);
		gmin(ans,cnt+i+solve(i==1)*2);
	}
	printf("%d\n",ans);
	return 0;
}

Measured memory_bytes: 384