#include <string>
#include <vector>
#include <algorithm>
#include <numeric>
#include <set>
#include <map>
#include <queue>
#include <iostream>
#include <sstream>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <cstring>
#include <cctype>
#include <cassert>
#include <limits>
#include <functional>
#define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define rer(i,l,u) for(int (i)=(int)(l);(i)<=(int)(u);++(i))
#define reu(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i))
#if defined(_MSC_VER) || __cplusplus > 199711L
#define aut(r,v) auto r = (v)
#else
#define aut(r,v) __typeof(v) r = (v)
#endif
#define each(it,o) for(aut(it, (o).begin()); it != (o).end(); ++ it)
#define all(o) (o).begin(), (o).end()
#define pb(x) push_back(x)
#define mp(x,y) make_pair((x),(y))
#define mset(m,v) memset(m,v,sizeof(m))
#define INF 0x3f3f3f3f
#define INFL 0x3f3f3f3f3f3f3f3fLL
using namespace std;
typedef vector<int> vi; typedef pair<int,int> pii; typedef vector<pair<int,int> > vpii; typedef long long ll;
template<typename T, typename U> inline void amin(T &x, U y) { if(y < x) x = y; }
template<typename T, typename U> inline void amax(T &x, U y) { if(x < y) x = y; }

struct DP {
	int n, x;
	vector<int> dp;
	DP(int n_, int x_) : n(n_), x(x_), dp((n_+1) * x_ * x_ * x_ * x_, -1) {}
	int &operator()(int i, int k, int u, int r, int o) {
		return dp[((((i * x + k) * x + u) * x + r) * x + o)];
	}
};

int main() {
	string S;
	while(cin >> S) {
		int n = S.size();
		int x = n / 5 + 1;
		DP dp(n, x + 1);
		dp(0, 0, 0, 0, 0) = 0;
		rep(i, n) rep(k, x) rep(u, x) rep(r, x) rep(o, x) {
			int t = dp(i, k, u, r, o);
			if(t == -1) continue;
			amax(dp(i + 1, k, u, r, o), t);
			if(S[i] == '?' || S[i] == 'K')
				amax(dp(i + 1, k + 1, u, r, o), t);
			if(S[i] == '?' || S[i] == 'U')
				if(k > 0) amax(dp(i + 1, k - 1, u + 1, r, o), t);
			if(S[i] == '?' || S[i] == 'R')
				if(u > 0) amax(dp(i + 1, k, u - 1, r + 1, o), t);
			if(S[i] == '?' || S[i] == 'O')
				if(r > 0) amax(dp(i + 1, k, u, r - 1, o + 1), t);
			if(S[i] == '?' || S[i] == 'I')
				if(o > 0) amax(dp(i + 1, k, u, r, o - 1), t + 1);
		}
		int ans = dp(n, 0, 0, 0, 0);
		printf("%d\n", ans);
	}
	return 0;
}