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

#undef _P
#define _P(...) (void)printf(__VA_ARGS__)
#define FORR(x,arr) for(auto&& x:arr)
#define FOR(i,a,b) for (int i = (a); i < (b); i++)
#define RFOR(i,a,b) for (int i = (b)-1; i >= (a); i--)
#define REP(i,n) for (int i = 0; i < (n); i++)
#define RREP(i,n) for (int i = (n)-1; i >= 0; i--)
#define ALL(x) (x).begin(), (x).end()
#define ITR(x,c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++)
#define RITR(x,c) for(__typeof(c.rbegin()) x=c.rbegin();x!=c.rend();x++)
#define BIT(n) (1LL<<(n))
#define SZ(x) ((int)(x).size())
typedef long long ll;
// -------------------------------------

string s;
int dp[2][21][21][21][21][21];

int main() {
  cin >> s;

  dp[0][0][0][0][0][0] = 1;

  int len = SZ(s);
  int ans = 0;
  REP(x, len) {
    char c = s[x];
    int y = x % 2;
    int z = !y;
    REP(k, 21) REP(u, k+1) REP(r, u+1) REP(o, r+1) REP(i, o+1) if (dp[y][k][u][r][o][i]) {
      if ((c == 'K' || c == '?') && k < 20) dp[z][k+1][u][r][o][i] = dp[y][k][u][r][o][i];
      if ((c == 'U' || c == '?') && u < k) dp[z][k][u+1][r][o][i] = dp[y][k][u][r][o][i];
      if ((c == 'R' || c == '?') && r < u) dp[z][k][u][r+1][o][i] = dp[y][k][u][r][o][i];
      if ((c == 'O' || c == '?') && o < r) dp[z][k][u][r][o+1][i] = dp[y][k][u][r][o][i];
      if ((c == 'I' || c == '?') && i < o) dp[z][k][u][r][o][i+1] = dp[y][k][u][r][o][i], ans = max(ans, i+1);
      else dp[z][k][u][r][o][i] = dp[y][k][u][r][o][i];
    }
  }

  cout << ans << endl;

  return 0;
}