#include<bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(int i=a;i<b;i++)


string S;
int dp[101][22][22][22][22];
//-----------------------------------------------------------------------------------
int main() {
    cin >> S;

    dp[0][0][0][0][0] = 1;
    int n = S.length();
    rep(i, 0, n) rep(K, 0, 21) rep(KU, 0, K + 1) rep(KUR, 0, KU + 1) rep(KURO, 0, KUR + 1) if(dp[i][K][KU][KUR][KURO]){
        if (S[i] == 'K' || S[i] == '?')
            dp[i + 1][K + 1][KU][KUR][KURO] = max(dp[i + 1][K + 1][KU][KUR][KURO], dp[i][K][KU][KUR][KURO]);
        if (S[i] == 'U' || S[i] == '?')
            dp[i + 1][K][KU + 1][KUR][KURO] = max(dp[i + 1][K][KU + 1][KUR][KURO], dp[i][K][KU][KUR][KURO]);
        if (S[i] == 'R' || S[i] == '?')
            dp[i + 1][K][KU][KUR + 1][KURO] = max(dp[i + 1][K][KU][KUR + 1][KURO], dp[i][K][KU][KUR][KURO]);
        if (S[i] == 'O' || S[i] == '?')
            dp[i + 1][K][KU][KUR][KURO + 1] = max(dp[i + 1][K][KU][KUR][KURO + 1], dp[i][K][KU][KUR][KURO]);
        if (S[i] == 'I' || S[i] == '?')
            if(dp[i][K][KU][KUR][KURO] <= KURO)
                dp[i + 1][K][KU][KUR][KURO] = max(dp[i + 1][K][KU][KUR][KURO], dp[i][K][KU][KUR][KURO] + 1);
        dp[i + 1][K][KU][KUR][KURO] = max(dp[i + 1][K][KU][KUR][KURO], dp[i][K][KU][KUR][KURO]);
    }

    int ans = 0;
    rep(K, 0, 21) rep(KU, 0, K + 1) rep(KUR, 0, KU + 1) rep(KURO, 0, KUR + 1)
        ans = max(ans, dp[n][K][KU][KUR][KURO]);
    ans--;
    printf("%d\n", ans);
}