#include "bits/stdc++.h" using namespace std; int main(){ int n,ans=0; string s; cin>>n>>s; for(int i=0,j=0;i<n;i++){ if(s[i]=='x'){ j=i+1; while(j<n&&s[j]=='x')j++; if(j-i>=3)ans+=(j-i-2); i=j-1; } } cout<<ans; }