#include <iostream>
#include <string>

using namespace std;

int numberOfLettersZ(string Sentence) {
    int n=0;

    for (int i = 0; i < Sentence.size(); i++)
        if (Sentence[i] == 'z')
            n++;

    return n;
}

int main()
{
    string firstSentence, secondSentence;

    getline(cin, firstSentence);
    getline(cin, secondSentence);

    cout << numberOfLettersZ(firstSentence) + numberOfLettersZ(secondSentence);
}