//https://ncode.syosetu.com/n4830bu/291/
#include <bits/stdc++.h>
using namespace std;

int main() {
    string S;
    cin >> S;
    string maine = "KUROI";
    vector dp(30, vector(30, vector(30, vector(30, -10000))));
    dp[0][0][0][0] = 0;
    for (auto&& c : S) {
        auto dp_nxt = dp;
        for (int idx0 = 0; idx0 < 20; idx0++) {
            for (int idx1 = 0; idx1 < 20; idx1++) {
                for (int idx2 = 0; idx2 < 20; idx2++) {
                    for (int idx3 = 0; idx3 < 20; idx3++) {
                        for (int i = 0; i < 5; i++) {
                            if (c == maine[i] || c == '?') {
                                if (i == 0)
                                    dp_nxt[idx0 + 1][idx1][idx2][idx3] = max(dp_nxt[idx0 + 1][idx1][idx2][idx3], dp[idx0][idx1][idx2][idx3]);
                                if (i == 1 && idx0 > 0)
                                    dp_nxt[idx0 - 1][idx1 + 1][idx2][idx3] = max(dp_nxt[idx0 - 1][idx1 + 1][idx2][idx3], dp[idx0][idx1][idx2][idx3]);
                                if (i == 2 && idx1 > 0)
                                    dp_nxt[idx0][idx1 - 1][idx2 + 1][idx3] = max(dp_nxt[idx0][idx1 - 1][idx2 + 1][idx3], dp[idx0][idx1][idx2][idx3]);
                                if (i == 3 && idx2 > 0)
                                    dp_nxt[idx0][idx1][idx2 - 1][idx3 + 1] = max(dp_nxt[idx0][idx1][idx2 - 1][idx3 + 1], dp[idx0][idx1][idx2][idx3]);
                                if (i == 4 && idx3 > 0)
                                    dp_nxt[idx0][idx1][idx2][idx3 - 1] = max(dp_nxt[idx0][idx1][idx2][idx3 - 1], dp[idx0][idx1][idx2][idx3] + 1);
                            }
                        }
                    }
                }
            }
        }
        swap(dp, dp_nxt);
    }
    int book = 0;
    for (int idx0 = 0; idx0 < 20; idx0++) {
        for (int idx1 = 0; idx1 < 20; idx1++) {
            for (int idx2 = 0; idx2 < 20; idx2++) {
                for (int idx3 = 0; idx3 < 20; idx3++) {
                    book = max(book, dp[idx0][idx1][idx2][idx3]);
                }
            }
        }
    }
    cout << book << endl;
}