#include <iostream>
using namespace std;

int main() {
	string a,c;
	int b;
	b = 0;
	cin >> a;
	c = "n";
	for(int i=0;i < a.length() ; i++){
		if(a[i] == c[0]){
			b++;
		}
	}
	cout << b++ << endl;
	return 0;
}