#include<iostream> #include<cstdio> #include<vector> #include<queue> #include<map> #include<set> #include<string> #include<algorithm> #include<functional> using namespace std; #define FOR(i,a,b) for (int i=(a);i<(b);i++) #define RFOR(i,a,b) for (int i=(b)-1;i>=(a);i--) #define REP(i,n) for (int i=0;i<(n);i++) #define RREP(i,n) for (int i=(n)-1;i>=0;i--) #define INF 1<<30 #define MP make_pair #define mp make_pair #define pb push_back #define PB push_back #define DEBUG(x) cout<<#x<<": "<<x<<endl #define ll long long #define ull unsigned long long int cnt[26]; int main(){ cin.tie(0); ios::sync_with_stdio(false); string s;cin>>s; int n=s.size(); REP(i,n){ cnt[s[i]-'a']++; } int ans = min(cnt['t'-'a'], min(cnt['r'-'a'], cnt['e'-'a']/2) ); cout<<ans<<endl; }