#include <iostream>
using namespace std;

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