#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define FORI(i, n) for(ll i = 0; i < n; i++)
#define FOR(i, n) for(ll i = 1; i <= n; i++)
typedef vector < ll > vl;
typedef set < ll > setl;
#define ff first
#define ss second
#define all(v) v.begin(), v.end()
#define pll pair<ll, ll>
#define db double
#define nll cout << "\n"
#define nl "\n"
#define sync ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
ll poww(ll a, ll b){
ll res = 1;
while(b){
if(b & 1)res *= a;
a *= a;
b >>= 1;
}
return res;
}
const ll mod = 998244353;
const int sz = 5e5 + 5 ;
const long long imax = LLONG_MAX;
ll n, m, k, res, q, x, y;
ll a[sz], b[sz];
ll pref[sz];
void solve(){
string s;
cin >> s;
char next = 'H';
ll cnt = 0;
for(auto i : s){
if(i == next){
if(i == 'H'){
next = 'O';
}
else if(i == 'O')next = 'N';
else if (i == 'N')next = 'I';
else if(i == 'I'){
next = 'H';
cnt++;
}
}
}
cout << cnt << nl;
}
//IOI rice hub
signed main(){
// freopen("input.txt","r",stdin);a
// freopen("output.txt","w",stdout);
sync;
ll t = 1;
// cin >> t;
while(t--){
solve();
}
}
