//205
#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <math.h>
#include <string>
#include <algorithm>
#include <climits>
using namespace std;


double gakkar(string s1, string s2)
{
    double c = 0;
    if (s1.length() <= s2.length())
    {
        for (int i = 0; i < s1.length(); i++) {
            if (s1[i] == s2[i])
                c++;
        }
    }
    else
    {
        for (int i = 0; i < s2.length(); i++)
            if (s1[i] == s2[i])
                c++;
    }
    c = c / (s1.length() + s2.length() - c);


    return c;



};

string norm2(string s)
{
    string x, k;
    int i = 0;

    while ((int)s[i] == 32)
        i++;

    for (; i<s.length(); i++)
    {
        if ((int)s[i] == 32)
            if (k.length() > 3)
            {
                x = x + k + " ";
                k = "";
            }
            else
                k = "";
        else
            k = k + s[i];
    }
    if (k.length() > 3)
        x = x + k;
    return x;
}

string norm1(string s)
{
    string x;
    for (int i = 0; i < s.length(); i++)
    {
        int a = (int)s[i];
        if ((a == 32) || ((a >= 48) && (a <= 57)) || ((a >= 97) && (a <= 122)))
            x = x + s[i];
        if ((a >= 65) && (a <= 90))
        {
            s[i] += 32;
            x = x + s[i];
        }
    }
    return x;
};


int main()
{
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
    string s1,s2, m;

    getline(cin, s1);
    getline(cin, s2);

    s1 = norm1(s1);
    s1 = norm2(s1);
    s2 = norm1(s2);
    s2 = norm2(s2);

    cout.precision(8);

    cout << fixed << gakkar(s1, s2);



    return 0;

}