#include <bits/stdc++.h>

#define show(x) cerr << #x << " = " << x << endl

using namespace std;
using ll = long long;

template <typename T>
ostream& operator<<(ostream& os, const vector<T>& v)
{
    os << "sz:" << v.size() << "\n[";
    for (const auto& p : v) {
        os << p << ",";
    }
    os << "]\n";
    return os;
}

template <typename S, typename T>
ostream& operator<<(ostream& os, const pair<S, T>& p)
{
    os << "(" << p.first << "," << p.second
       << ")";
    return os;
}


constexpr ll MOD = (ll)1e9 + 7LL;

template <typename T>
constexpr T INF = numeric_limits<T>::max() / 64;

int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);

    vector<int> num(14, 0);
    int pos = 0;
    for (int i = 0; i < 14; i++) {
        char c;
        cin >> c;
        if (c == 'x') {
            pos++;
        } else {
            num[pos]++;
        }
    }
    cout << *max_element(num.begin(), num.end()) << endl;

    return 0;
}