#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
//#include<cctype>
#include<climits>
#include<iostream>
#include<string>
#include<vector>
#include<map>
//#include<list>
#include<queue>
#include<deque>
#include<algorithm>
//#include<numeric>
#include<utility>
#include<complex>
//#include<memory>
#include<functional>
#include<cassert>
#include<set>
#include<stack>

const int dx[] = {1, 0, -1, 0};
const int dy[] = {0, 1, 0, -1};
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef pair<int, int> pii;

int dp[101][21][21][21][21];

void chmax(int& x, int y) {
    x = max(x, y);
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    string s;
    cin >> s;
    int n = s.size();
    memset(dp, -1, sizeof(dp));
    dp[0][0][0][0][0] = 0;
    for (int i = 0; i < n; i++) for (int k = 0; k <= 20; k++) for (int u = 0; u <= 20; u++) for (int r = 0; r <= 20; r++) for (int o = 0; o <= 20; o++) {
        chmax(dp[i+1][k][u][r][o], dp[i][k][u][r][o]);
        if (dp[i][k][u][r][o] == -1) continue;
        switch (s[i]) {
            case 'K':
                chmax(dp[i+1][min(k+1, 20)][u][r][o], dp[i][k][u][r][o]);
                break;
            case 'U':
                if (k > 0) chmax(dp[i+1][k-1][min(u+1, 20)][r][o], dp[i][k][u][r][o]);
                break;
            case 'R':
                if (u > 0) chmax(dp[i+1][k][u-1][min(r+1, 20)][o], dp[i][k][u][r][o]);
                break;
            case 'O':
                if (r > 0) chmax(dp[i+1][k][u][r-1][min(o+1, 20)], dp[i][k][u][r][o]);
                break;
            case 'I':
                if (o > 0) chmax(dp[i+1][k][u][r][o-1], dp[i][k][u][r][o]+1);
                break;
            case '?':
                chmax(dp[i+1][min(k+1, 20)][u][r][o], dp[i][k][u][r][o]);
                if (k > 0) chmax(dp[i+1][k-1][min(u+1, 20)][r][o], dp[i][k][u][r][o]);
                if (u > 0) chmax(dp[i+1][k][u-1][min(r+1, 20)][o], dp[i][k][u][r][o]);
                if (r > 0) chmax(dp[i+1][k][u][r-1][min(o+1, 20)], dp[i][k][u][r][o]);
                if (o > 0) chmax(dp[i+1][k][u][r][o-1], dp[i][k][u][r][o]+1);
                break;
            default:
                break;
        }
    }
    int ans = 0;
    for (int k = 0; k <= 20; k++) for (int u = 0; u <= 20; u++) for (int r = 0; r <= 20; r++) for (int o = 0; o <= 20; o++) ans = max(ans, dp[n][k][u][r][o]);
    cout << ans << endl;
    return 0;
}