#include <iostream>
#include <cstring>
#include <cstdio>
#include <algorithm>
using namespace std;
const int N = 110;
char a[N];
int n;
int cnt = 0;

int main()
{
    cin>>n;
    for(int i=0;i<n;i++)  scanf("%s",&a[i]);

    for(int i=0;i<n-2;i++)
    {
        if(a[i] == a[i + 1] && a[i + 2] == a[i + 1] && a[i] == 'x')
            cnt ++;
    }

    cout<<cnt<<endl;
    return 0;
}