Code

#include <iostream>
#define ushort unsigned short
using namespace std;

int main() {
  ushort n;
  cin >> n;
  short *a = (short*) calloc(n, sizeof(*a));
  for(ushort i = 0; i < n; i++) cin >> a[i];
  ushort d = 0;
  for(ushort i = 1; i < n; i++) {
    d += !(a[i-1] % 10) && !(a[i] % 10);
  }
  cout << d;
  free(a);
}