#include <algorithm>
#include <iostream>
#include <cstdlib>
#include <cstdarg>
#include <cassert>
#include <cstring>
#include <cstdio>
#include <vector>
#include <string>
#include <queue>
#include <set>
#include <map>

using namespace std;

typedef long long LL;
typedef long double LD;

#define all(c) (c).begin(),(c).end()
#define sz(c) (int)(c).size()

#define pb push_back
#define mp make_pair
#define fs first
#define sc second
#define y1 y1_gedjcdgfce
#define y0 y0_sadasdasdsa
#define ws ws_sadsadsada
#define left left_asdsadsadsadsa
#define right right_asdasdsadasda
#define hash hash_asdasdasdsad

#define eprintf(...) {fprintf(stderr,__VA_ARGS__),fflush(stderr);}
#define forn(i,n) for( int i = 0 ; i < (n) ; i++ )
#define forit(it,c) for( __typeof((c).begin()) it = (c).begin() ; it != (c).end() ; it++ )

#ifdef WIN32
#define INT64 "%I64d"
#else
#define INT64 "%lld"
#endif

#define TASK "task"

const int maxn = 113;

int term[maxn];
int next[maxn][2];
int suf[maxn];
char str[maxn];
int len[maxn];
int p[maxn];
int size = 2;

int cmplen(int a, int b) {
    return len[a] < len[b];
}

int go(int s, int ch) {
    if (next[s][ch] != -1) return next[s][ch];
    return go(suf[s], ch);
}

long double res[maxn][maxn];
long double tmp[maxn][maxn];

int main(){
    memset(next, -1, sizeof next);
    memset(suf, -1, sizeof suf);
    memset(term, 0, sizeof term);
    next[0][0] = next[0][1] = 1;
    len[0] = -2;
    len[1] = -1;
    suf[1] = 0;
    for (int k = 0; k < 2; k++) {
        scanf("%s", str);
        int p = 1;
        for (int i = 0; str[i]; i++) {
            if (next[p][str[i] - '0'] == -1) {
                next[p][str[i] - '0'] = size++;
            }
            p = next[p][str[i] - '0'];
            len[p] = i;
        }
        term[p] |= 1 << k;
    }
    for (int i = 0; i < size; i++) p[i] = i;
    sort(p, p + size, cmplen);
    for (int i = 1; i < size; i++) {
        if (next[p[i]][0] != -1) {
            suf[next[p[i]][0]] = go(suf[p[i]], 0);
        }
        if (next[p[i]][1] != -1) {
            suf[next[p[i]][1]] = go(suf[p[i]], 1);
        }
    }
    for (int i = 2; i < size; i++) {
        term[p[i]] |= term[suf[p[i]]];
    }
    for (int i = 1; i < size; i++) {
        if (term[i] != 0) {
            res[i][i] = 1.;
            continue;
        }
        res[i][go(i, 0)] = 0.5;
        res[i][go(i, 1)] = 0.5;
    }
    for (int iter = 0; iter < 200; iter++) {
        for (int i = 0; i < size; i++)
            for (int j = 0; j < size; j++)
                tmp[i][j] = 0.;
        for (int i = 0; i < size; i++)
            for (int j = 0; j < size; j++)
                for (int k = 0; k < size; k++)
                    tmp[i][j] += res[i][k] * res[k][j];
        for (int i = 0; i < size; i++)
            for (int j = 0; j < size; j++)
                res[i][j] = tmp[i][j];
    }
    long double answer = 0.;
    for (int i = 1; i < size; i++) {
        if (term[i] == 1) answer += res[1][i];
    }
    printf("%.20lf\n", (double)answer);
    return 0;
}