#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
#define REP(i,n) for(int i=0,_n=(int)(n);i<_n;++i)
#define ALL(v) (v).begin(),(v).end()
#define CLR(t,v) memset(t,(v),sizeof(t))
template<class T1,class T2>ostream& operator<<(ostream& os,const pair<T1,T2>&a){return os<<"("<<a.first<<","<<a.second<< ")";}
template<class T>void pv(T a,T b){for(T i=a;i!=b;++i)cout<<(*i)<<" ";cout<<endl;}
template<class T>void chmin(T&a,const T&b){if(a>b)a=b;}
template<class T>void chmax(T&a,const T&b){if(a<b)a=b;}

int nextInt() { int x; scanf("%d", &x); return x;}

const int M = 21;
int dp[2][M][M][M][M];

int main2() {
  CLR(dp, 0);

  string s; cin >> s;
  int N = s.size();

  REP(a, M) REP(b, M) REP(c, M) REP(d, M) dp[0][a][b][c][d] = -1001001001;
  dp[0][0][0][0][0] = 0;

  int f = 0;
  REP(i, N) {
    if (string("KUROI?").find(s[i]) == string::npos) continue;
    int nf = 1 - f;
    REP(a, M) REP(b, M) REP(c, M) REP(d, M) dp[nf][a][b][c][d] = -1001001001;
    REP(a, M) REP(b, M) REP(c, M) REP(d, M) {
      const int cur =  dp[f][a][b][c][d];
      chmax(dp[nf][a][b][c][d], cur);
      if (s[i] == 'K' || s[i] == '?')            chmax(dp[nf][min(20, a+1)][b][c][d], cur);
      if ((s[i] == 'U' || s[i] == '?') && a > 0) chmax(dp[nf][a-1][min(20, b+1)][c][d], cur);
      if ((s[i] == 'R' || s[i] == '?') && b > 0) chmax(dp[nf][a][b-1][min(20, c+1)][d], cur);
      if ((s[i] == 'O' || s[i] == '?') && c > 0) chmax(dp[nf][a][b][c-1][min(20, d+1)], cur);
      if ((s[i] == 'I' || s[i] == '?') && d > 0) chmax(dp[nf][a][b][c][d-1], cur + 1);
    }
    f = 1 - f;
  }

  int ans = 0;
  REP(a, M) REP(b, M) REP(c, M) REP(d, M) chmax(ans, dp[f][a][b][c][d]);
  cout << ans << endl;
  return 0;
}

int main() {

#ifdef LOCAL
  for (;!cin.eof();cin>>ws)
#endif
    main2();
  return 0;
}