//No.418 ミンミンゼミ

#include <bits/stdc++.h>
using namespace std;

int main()
{
int i;
int iCnt;
char C;
char S[ 110 ];

	cin >> S;

	iCnt = 0;
	i = 0;
	C = S[ i ];
	while( C != '\0' )
	{
		if( C == 'n' ) iCnt++;

		i++;
		C = S[ i ];
	}

	cout << iCnt << endl;

	return 0;
}