/* -*- coding: utf-8 -*-
 *
 * 291.cc: No.291 黒い文字列 - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int MAX_N = 100;
const int MAX_M = MAX_N / 5;

/* typedef */

typedef vector<int> vi;

/* global variables */

vi as;
int dp[2][MAX_M + 1][MAX_M + 1][MAX_M + 1][MAX_M + 1];

/* subroutines */

/* main */

int main() {
  string s;
  cin >> s;

  for (int i = 0; i < s.size(); i++)
    switch (s[i]) {
    case 'K': as.push_back(0); break;
    case 'U': as.push_back(1); break;
    case 'R': as.push_back(2); break;
    case 'O': as.push_back(3); break;
    case 'I': as.push_back(4); break;
    case '?': as.push_back(-1); break;
    }

  int n = as.size();
  int m = n / 5;
  //for (int i = 0; i < n; i++) printf("%d ", as[i]); putchar('\n');

  memset(dp, -1, sizeof(dp));
  dp[0][0][0][0][0] = 0;
  int cur = 0, nxt = 1;

  for (int i = 0; i < n; i++) {
    int &ai = as[i];
    for (int k = 0; k <= m; k++)
      for (int u = 0; u <= m; u++)
	for (int r = 0; r <= m; r++)
	  for (int o = 0; o <= m; o++) {
	    int &dpc = dp[cur][k][u][r][o];
	    if (dpc >= 0) {
	      if (ai < 0) {
		int k0 = min(m, k + 1);
		if (dp[nxt][k0][u][r][o] < dpc) dp[nxt][k0][u][r][o] = dpc;
		int u0 = min(k, u + 1);
		if (dp[nxt][k][u0][r][o] < dpc) dp[nxt][k][u0][r][o] = dpc;
		int r0 = min(u, r + 1);
		if (dp[nxt][k][u][r0][o] < dpc) dp[nxt][k][u][r0][o] = dpc;
		int o0 = min(r, o + 1);
		if (dp[nxt][k][u][r][o0] < dpc) dp[nxt][k][u][r][o0] = dpc;
		if (k > 0 && u > 0 && r > 0 && o > 0) {
		  int d0 = dpc + 1;
		  if (dp[nxt][k - 1][u - 1][r - 1][o - 1] < d0)
		    dp[nxt][k - 1][u - 1][r - 1][o - 1] = d0;
		}
	      }
	      else if (ai == 0) {
		int k0 = min(m, k + 1);
		if (dp[nxt][k0][u][r][o] < dpc) dp[nxt][k0][u][r][o] = dpc;
	      }
	      else if (ai == 1) {
		int u0 = min(k, u + 1);
		if (dp[nxt][k][u0][r][o] < dpc) dp[nxt][k][u0][r][o] = dpc;
	      }
	      else if (ai == 2) {
		int r0 = min(u, r + 1);
		if (dp[nxt][k][u][r0][o] < dpc) dp[nxt][k][u][r0][o] = dpc;
	      }
	      else if (ai == 3) {
		int o0 = min(r, o + 1);
		if (dp[nxt][k][u][r][o0] < dpc) dp[nxt][k][u][r][o0] = dpc;
	      }
	      else if (ai == 4) {
		if (k > 0 && u > 0 && r > 0 && o > 0) {
		  int d0 = dpc + 1;
		  if (dp[nxt][k - 1][u - 1][r - 1][o - 1] < d0)
		    dp[nxt][k - 1][u - 1][r - 1][o - 1] = d0;
		}
	      }
	    }
	  }
    cur ^= 1, nxt ^= 1;
  }

  int maxd = 0;
  for (int k = 0; k <= m; k++)
    for (int u = 0; u <= m; u++)
      for (int r = 0; r <= m; r++)
	for (int o = 0; o <= m; o++)
	  if (maxd < dp[cur][k][u][r][o]) maxd = dp[cur][k][u][r][o];

  printf("%d\n", maxd);
  return 0;
}