#define _CRT_SECURE_NO_WARNINGS
#include<sstream>
#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<climits>
#include<cmath>
#include<string>
#include<vector>
#include<set>
#include<map>
#include<queue>
#include<numeric>
#include<functional>
#include<algorithm>
#include<bitset>
#include<tuple>
#include<unordered_set>
#include<random>
using namespace std;
#define INF (1<<29)
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define all(v) v.begin(),v.end()
#define uniq(v) v.erase(unique(all(v)),v.end())
#define indexOf(v,x) (find(all(v),x)-v.begin())


char *c = "KUROI";

int count(string s) {
	int cnt = 0;
	while (1) {
		int i = 0;
		bool k = false;
		rep(j, s.size()) {
			if (c[i] == s[j]) {
				i++;
				if (i == 5) {
					i = 0;
					cnt++;
					k = true;
				}
				s[j] = '.';
			}
		}
		if (!k)break;
	}
	return cnt;
}
bool f(string s, int n) {
	int a[5] = {};
	rep(i, s.size()) {
		if (s[i] != '?') {
			if (s[i] == 'K')a[0]++;
			else if (s[i] == 'U'&&a[0]>a[1])a[1]++;
			else if (s[i] == 'R'&&a[1]>a[2])a[2]++;
			else if (s[i] == 'O'&&a[2]>a[3])a[3]++;
			else if (s[i] == 'I'&&a[3]>a[4])a[4]++;
		}
		else {
			rep(j, 5) {
				if (a[j]<n) {
					s[i] = c[j];
					a[j]++;
					break;
				}
			}
		}
	}
	return n <= count(s);
}


int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	string s;
	cin >> s;
	int ans = 0;
	rep(i, s.size() / 5 + 1) {
		if (f(s, i))ans = i;
	}
	cout << ans << endl;

	return 0;
}