#include <bits/stdc++.h>
#define db double
#define il inline
#define re register
#define ll long long
#define ui unsigned
#define ull ui ll
#define i128 __int128
#define pii pair<int, int>
#define fi first
#define se second
#define eb emplace_back
#define SZ(v) (int)v.size()
#define ALL(v) v.begin(), v.end()
#define mems(v, x) memset(v, x, sizeof(v))
#define memc(a, b) memcpy(a, b, sizeof(a))
#define FOR(i, L, R) for(re int i = (L); i <= (R); ++i)
#define ROF(i, R, L) for(re int i = (R); i >= (L); --i)
#define LS i << 1, l, mid
#define RS i << 1 | 1, mid + 1, r
#define popc(x) __builtin_popcount(x)
using namespace std;
#define N 505
#define P 1000000007
il int add(int x, int y) {return x + y < P ? x + y : x + y - P;}
il void addr(int &x, int y) {(x += y) >= P && (x -= P);}
il int qpow(int p, int n = P - 2) {
  int s = 1;
  while(n) {
    if(n & 1) s = 1ll * s * p % P;
    p = 1ll * p * p % P, n >>= 1;
  }
  return s;
}
const int mu = qpow(1e4);
int n; string str;
il void WORK() {
  str = " " + str; int s = 0;
  FOR(i, 1, n - 3) {
    if(str.substr(i, 4) == "2020") ++s, i += 3;
  }
  cout << s << "\n";
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0), cout.tie(0);
  while(cin >> n >> str) WORK();
  cerr << 1.0 * clock() / CLOCKS_PER_SEC;
  return 0;
}