#include <iostream>
#include <string>
using namespace std;
int main(){

  int n,tmp=0;
  string s;
  cin>>n>>s;
  for(int i=0;i<n;i++){
    if(s[i]=='o') tmp=0;
    else tmp++;
    if(tmp==2){
      cout<<i<<endl;
      return 0;
    }
  }
  cout<<n<<endl;
  return 0;

}