#include <bits/stdc++.h>
using namespace std;

typedef long long   signed int LL;
typedef long long unsigned int LU;

#define incID(i, l, r) for(int i = (l)    ; i <  (r); i++)
#define incII(i, l, r) for(int i = (l)    ; i <= (r); i++)
#define decID(i, l, r) for(int i = (r) - 1; i >= (l); i--)
#define decII(i, l, r) for(int i = (r)    ; i >= (l); i--)
#define  inc(i, n) incID(i, 0, n)
#define inc1(i, n) incII(i, 1, n)
#define  dec(i, n) decID(i, 0, n)
#define dec1(i, n) decII(i, 1, n)

#define inII(v, l, r) ((l) <= (v) && (v) <= (r))
#define inID(v, l, r) ((l) <= (v) && (v) <  (r))

#define PB push_back
#define EB emplace_back
#define MP make_pair
#define FI first
#define SE second
#define UB upper_bound
#define LB lower_bound
#define PQ priority_queue

#define  ALL(v)  v.begin(),  v.end()
#define RALL(v) v.rbegin(), v.rend()
#define  FOR(it, v) for(auto it =  v.begin(); it !=  v.end(); ++it)
#define RFOR(it, v) for(auto it = v.rbegin(); it != v.rend(); ++it)

template<typename T> bool   setmin(T & a, T b) { if(b <  a) { a = b; return true; } else { return false; } }
template<typename T> bool   setmax(T & a, T b) { if(b >  a) { a = b; return true; } else { return false; } }
template<typename T> bool setmineq(T & a, T b) { if(b <= a) { a = b; return true; } else { return false; } }
template<typename T> bool setmaxeq(T & a, T b) { if(b >= a) { a = b; return true; } else { return false; } }
template<typename T> T gcd(T a, T b) { return (b == 0 ? a : gcd(b, a % b)); }
template<typename T> T lcm(T a, T b) { return a / gcd(a, b) * b; }

// ---- ----

string s;
int dp[101][22][22][22][22], ans = 1;

int main() {
	cin >> s;
	
	int n = s.size(), m = n / 5 + 1;
	dp[0][0][0][0][0] = 1; // + 1
	inc(i, n) {
	inc(k, m) {
	inc(u, m) {
	inc(r, m) {
	inc(o, m) {
		int v = dp[i][k][u][r][o];
		if(v == 0) { continue; }
		setmax(dp[i + 1][k][u][r][o], v);
		if( s[i] == 'K' || s[i] == '?'           ) { setmax(dp[i + 1][k + 1][u][r][o], v); }
		if((s[i] == 'U' || s[i] == '?') && k != 0) { setmax(dp[i + 1][k - 1][u + 1][r][o], v); }
		if((s[i] == 'R' || s[i] == '?') && u != 0) { setmax(dp[i + 1][k][u - 1][r + 1][o], v); }
		if((s[i] == 'O' || s[i] == '?') && r != 0) { setmax(dp[i + 1][k][u][r - 1][o + 1], v); }
		if((s[i] == 'I' || s[i] == '?') && o != 0) { setmax(dp[i + 1][k][u][r][o - 1], v + 1); setmax(ans, v + 1); }
	}
	}
	}
	}
	}
	
	cout << ans - 1 << endl; // -1
	
	return 0;
}