#include <algorithm>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <iostream>
#include <map>
#include <memory>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>

using namespace std;

#define sz size()
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define all(c) (c).begin(), (c).end()
#define rep(i,a,b) for(int i=(a);i<(b);++i)
#define clr(a, b) memset((a), (b) ,sizeof(a))

#define MOD 1000000007

int dp[2][22][22][22][22][22];

int main() {
    clr(dp,0);
    string s;
    cin>>s;
    if(s[0]=='K'||s[0]=='?'){
      dp[0][1][0][0][0][0] = 1;
    }
    else{
      dp[0][0][0][0][0][0] = 1;
    }
    int old = 0;
    int now = 1;
    rep(j,1,s.sz){
        rep(k,0,21){
          rep(u,0,21){
            rep(r,0,21){
              rep(o,0,21){
                rep(i,0,21){
                  if(s[j]=='?'){
                    dp[now][k+1][u][r][o][i] += dp[old][k][u][r][o][i];
                    if(k>u)dp[now][k][u+1][r][o][i] += dp[old][k][u][r][o][i];
                    if(u>r)dp[now][k][u][r+1][o][i] += dp[old][k][u][r][o][i];
                    if(r>o)dp[now][k][u][r][o+1][i] += dp[old][k][u][r][o][i];
                    if(o>i)dp[now][k][u][r][o][i+1] += dp[old][k][u][r][o][i];
                  }
                  else if(s[j]=='K'){
                    dp[now][k+1][u][r][o][i] += dp[old][k][u][r][o][i];
                  }
                  else if(s[j]=='U'){
                    if(k>u)dp[now][k][u+1][r][o][i] += dp[old][k][u][r][o][i];
                  }
                  else if(s[j]=='R'){
                    if(u>r)dp[now][k][u][r+1][o][i] += dp[old][k][u][r][o][i];
                  }
                  else if(s[j]=='O'){
                    if(r>o)dp[now][k][u][r][o+1][i] += dp[old][k][u][r][o][i];
                  }
                  else if(s[j]=='I'){
                    if(o>i)dp[now][k][u][r][o][i+1] += dp[old][k][u][r][o][i];
                  }
                  else{
                    dp[now][k][u][r][o][i] += dp[old][k][u][r][o][i];
                  }
                }
              }
            }
          }
        }
        clr(dp[old],0);
        old = 1-old;
        now = 1-now;
    }
    int mx = 0;
    rep(k,0,21){
          rep(u,0,21){
            rep(r,0,21){
              rep(o,0,21){
                rep(i,0,21){
                  if(dp[old][k][u][r][o][i] > 0){
                    mx = max(mx,min(k,min(u,min(r,min(o,i)))));
                  }
                }
              }
            }
          }
    }
    cout << mx << endl;
    return 0;
}