#include <iostream>
using namespace std;
int main(){
    char c;
    int count=0, max_count = -1;;
    while(cin >> c){
        if(c =='o'){
            count++;
        }else if(c =='x'){
            max_count = max(count, max_count);
            count = 0;
            continue;
        }

    }
    max_count = max(count, max_count);
    cout << max_count << endl;
    return 0;
}