#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <stdio.h>
#include <cstring>
#include <queue>
#include <stack>
#include <functional>
#include <math.h>
#include <iomanip>
using namespace std;
#define Would
#define you
const int INF = 999999999;
const int MOD = 1e9 + 7;

int main() {
	char a[14];
	for (int i = 0; i < 14; ++i) { cin >> a[i]; }
	int ans, cou = 0;
	for (int i = 0; i < 14; ++i) {
		if (a[i] == 'x') { cou = 0; }
		else { ++cou; }
		ans = max(ans, cou);
	}
	cout << ans << endl;
}