#include <bits/stdc++.h>
using namespace std;
int main()
{
    string s;
    map<char,int> n;
    cin>>s;
    for(int i=0;i<s.length();i++)if(s[i]=='t'||s[i]=='r'||s[i]=='e')n[s[i]]++;
    n['e']/=2;int m=n['e'];
    for(auto i=n.begin();i!=n.end();i++)if(m>i->second)m=i->second;
    cout<<m<<endl;
    return 0;
}