#include <string>
#include <vector>
#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<stack>
#include<queue>
#include<cmath>
#include<algorithm>
#include<functional>
#include<list>
#include<deque>
#include<bitset>
#include<set>
#include<map>
#include<unordered_map>
#include<cstring>
#include<sstream>
#include<complex>
#include<iomanip>
#include<numeric>
#define X first
#define Y second
#define pb push_back
#define rep(X,Y) for (int (X) = 0;(X) < (Y);++(X))
#define rrep(X,Y) for (int (X) = (Y)-1;(X) >=0;--(X))
#define repe(X,Y) for ((X) = 0;(X) < (Y);++(X))
#define peat(X,Y) for (;(X) < (Y);++(X))
#define all(X) (X).begin(),(X).end()
#define rall(X) (X).rbegin(),(X).rend()
#define eb emplace_back
#define UNIQUE(X) (X).erase(unique(all(X)),(X).end())

using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
template<class T> using vv=vector<vector<T>>;
template<class T> ostream& operator<<(ostream &os, const vector<T> &t) {
os<<"{"; rep(i,t.size()) {os<<t[i]<<",";} os<<"}"<<endl; return os;}
template<class S, class T> ostream& operator<<(ostream &os, const pair<S,T> &t) { return os<<"("<<t.first<<","<<t.second<<")";}
const ll MOD=1e9+7;

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

int main(){
  ios_base::sync_with_stdio(false);
  cout<<fixed<<setprecision(0);
  string str;
  cin>>str;
  fill(dp[0][0][0][0],dp[0][0][0][0]+2*22*22*22*22,-MOD);
  int x=0,y=1;
  dp[0][0][0][0][0]=0;
  int n=str.size();
  rep(i,n){
    fill(dp[y][0][0][0],dp[y][0][0][0]+22*22*22*22,-MOD);
    rep(k,21)rep(u,21)rep(r,21)rep(o,21){
      const char c=str[i];
      if(c=='K' || c=='?')
	dp[y][k+1][u][r][o]=max(dp[y][k+1][u][r][o],dp[x][k][u][r][o]);
      if(c=='U' || c=='?')if(k)
	dp[y][k-1][u+1][r][o]=max(dp[y][k-1][u+1][r][o],dp[x][k][u][r][o]);
      if(c=='R' || c=='?')if(u)
	dp[y][k][u-1][r+1][o]=max(dp[y][k][u-1][r+1][o],dp[x][k][u][r][o]);
      if(c=='O' || c=='?')if(r)
	dp[y][k][u][r-1][o+1]=max(dp[y][k][u][r-1][o+1],dp[x][k][u][r][o]);
      if(c=='I' || c=='?')if(o)
	dp[y][k][u][r][o-1]=max(dp[y][k][u][r][o-1],dp[x][k][u][r][o]+1);
      dp[y][k][u][r][o]=max(dp[y][k][u][r][o],dp[x][k][u][r][o]);
    }
    swap(x,y);
  }
  cout<<*max_element(dp[n%2][0][0][0],dp[n%2][0][0][0]+22*22*22*22)<<endl;
  return 0;
}