import java.util.Scanner;

public class Main {
    public static void main(String[] args){
        Scanner sc=new Scanner(System.in);
        //ここから処理開始
        String s=sc.next();
        int ret = 0;
        for (int i = 0; i < s.length(); i++) {
            if(s.charAt(i)=='i')ret++;
        }
        System.out.println(ret);
        //ここまで
        sc.close();
    }
}