import java.util.*;public class DemoTest5 {public static void main(String[] args) {Scanner in = new Scanner(System.in);// 注意 hasNext 和 hasNextLine 的区别while (in.hasNextLine()) { // 注意 while 处理多个 caseSystem.out.println(solve(in.nextLine()));}}private static int solve(String s){char[] chars = s.toCharArray();int count = 0;boolean[]  used= new boolean[chars.length];for (int i=0;i<chars.length;i++){if(chars[i] == 'M'){if(i-1>=0 && chars[i-1]=='I'&& !used[i - 1]) {count++;used[i-1] = true;}else if (i+1< chars.length && chars[i+1]=='I' && !used[i + 1]){count++;used[i+1] = true;}}}return count >0? count:-1;}
}