#include<iostream>
#include<cmath>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<iomanip>
#include<assert.h>
#include<vector>
#include<list>
#include<map>
#include<set>
#include<sstream>
#include<stack>
#include<queue>
#include<string>
#include<bitset>
#include<algorithm>
using namespace std;
#define me(s)  memset(s,0,sizeof(s))
#define _for(i,a,b) for(int i=(a);i<(b);++i)
#define _rep(i,a,b) for(int i=(a);i<=(b);++i)
#define mp make_pair
#define pb push_back
#define all(x) (x).begin(),(x).end()
#define F first
#define S second
#define Di(x) int x;scanf("%d",&x)
#define in(x) inp(x)
#define in2(x,y) inp(x),inp(y)
#define in3(x,y,z) inp(x),inp(y),inp(z)
#define ins(x) scanf("%s",x)
#define ind(x) scanf("%lf",&x)
#define IO ios_base::sync_with_stdio(0);cin.tie(0)
#define READ freopen("C:/Users/ASUS/Desktop/in.txt","r",stdin)
#define WRITE freopen("C:/Users/ASUS/Desktop/out.txt","w",stdout)
template<class T> void inp(T &x) {//读入优化
    char c = getchar(); x = 0;
    for (; (c < 48 || c>57); c = getchar());
    for (; c > 47 && c < 58; c = getchar()) { x = (x << 1) + (x << 3) + c - 48; }
}
typedef pair <int, int> pii;
typedef long long ll;
typedef unsigned long long ull;
const int inf = 0x3f3f3f3f;
const int mod = 1e9 + 7;
const double pi = acos(-1.0);
const double eps = 1e-15;
bool check(string a,string b,int st1,int st2,int n){
    for(int i=0;i<n;i++)
    if(a[st1+i]=='2'&&b[st2+i]=='2') return 0;
    return 1;
}
string a,b;
int n1,n2;
void Solve(){
   int ans=n1+n2;
   for(int i=0;i<n1;i++){
       if(check(a,b,i,0,min(n1-i,n2))) ans=min(ans,max(i+n2,n1));
   }
   for(int i=0;i<n2;i++){
       if(check(b,a,i,0,min(n2-i,n1))) ans=min(ans,max(i+n1,n2));
   }
   printf("%d\n",ans);
}
int Input(){
    if(cin>>a) cin>>b;
    else return 0;
    n1=a.length();n2=b.length();
    return 1;
}
int main(){
    //READ;
    //WRITE;
    while(Input())
    Solve();
}