#include<bits/stdc++.h>
using namespace std;
#define int long long
#define pb push_back
#define F first
#define S second
signed main(){
	ios_base::sync_with_stdio(NULL);
	cin.tie(NULL);
	cout.tie(NULL);
	string s;
	cin >> s;
	int cnt = 0;
	for(int i = 4; i < s.size(); i ++ ){
		if( s[i-4] = 'e' && s[i-3] == 'd' && s[i-2] == 'g' && s[i-1] == 'n' && s[i] == 'b' ){
			cnt ++;
		}
	}
	cout << cnt << "\n";
}