#include <iostream>
#include <string.h>
#include <vector>
using namespace std;

int main(){
  /*
  const int count = 14;
  std::vector<char> day(14);
  for (size_t i = 0; i < count; i++){
    cin >> day[i];
    if(day[i]=='x')
    cout << "aaa";
  }
  */
  const int count = 14;
  char a;
  int result=0,num=0;
  for (size_t i = 0; i < count; i++) {
    cin >> a;
    (a == 'x')?(num = 0):(num = num+1);
    (num > result)?(result = num):(0);
  }
  cout << result << endl;
}