#include <iostream>

 #include <cstdio>

 #include <string>

 #include <algorithm>

 using namespace std;

 const int INF = 0x3f3f3f3f;

 int ch[], ci[], co[];

 bool check(int pos, int a, int b, int c)

 {

     return ch[pos] <= a -  && ci[pos] <= b -  && co[pos] <= c - ;

 }

 int main()

 {

     string s;

     cin >> s;

     int n = s.length();

     ch[] += (s[] == 'h');

     ci[] += (s[] == 'i');

     co[] += (s[] == 'o');

     int last = , min_len = INF;

     for (int i = ; i < n; i++)

     {

         ch[i] = ch[i - ] + (s[i] == 'h');

         ci[i] = ci[i - ] + (s[i] == 'i');

         co[i] = co[i - ] + (s[i] == 'o');

         if (ch[i] >=  && ci[i] >=  && co[i] >= )

         {

             while (last < i && check(last, ch[i], ci[i], co[i]))

             {

                 last++;

             }

             if (ch[i] - ch[last - ] ==  &&

                 ci[i] - ci[last - ] ==  &&

                 co[i] - co[last - ] == )

                 min_len = min(min_len, i - last + );

         }

     }

     if (min_len != INF)

         cout << min_len << endl;

     else

         cout << - << endl;

     return ;

 }