import std.conv, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.container, std.math, std.numeric, std.range, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }
real readReal() { return readToken.to!real; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(T)(in T[] as, in bool delegate(T) test) { int low = -1, upp = cast(int)(as.length); for (; low + 1 < upp; ) { int mid = (low + upp) >> 1; (test(as[mid]) ? low : upp) = mid; } return upp; }
int lowerBound(T)(in T[] as, in T val) { return as.binarySearch((T a) => (a < val)); }
int upperBound(T)(in T[] as, in T val) { return as.binarySearch((T a) => (a <= val)); }


int N;
string S;

void main() {
  try {
    for (; ; ) {
      S = readToken();
      N = cast(int)(S.length);
      const M = N / 5 + 1;
      auto crt = new int[M^^4];
      crt[] = -1;
      crt[0] = 0;
      foreach (c; S) {
        auto nxt = crt.dup;
        foreach_reverse (key; 0 .. M^^4) {
          if (crt[key] >= 0) {
            const m0 = key % M;
            const m1 = (key / M) % M;
            const m2 = (key / M^^2) % M;
            const m3 = (key / M^^3) % M;
            if ((c == 'K' || c == '?') && m0 + 1 < M) {
              chmax(nxt[key + 1], crt[key]);
            }
            if ((c == 'U' || c == '?') && m0 > 0 && m1 + 1 < M) {
              chmax(nxt[key - 1 + M], crt[key]);
            }
            if ((c == 'R' || c == '?') && m1 > 0 && m2 + 1 < M) {
              chmax(nxt[key - M + M^^2], crt[key]);
            }
            if ((c == 'O' || c == '?') && m2 > 0 && m3 + 1 < M) {
              chmax(nxt[key - M^^2 + M^^3], crt[key]);
            }
            if ((c == 'I' || c == '?') && m3 > 0) {
              chmax(nxt[key - M^^3], crt[key] + 1);
            }
          }
        }
        crt = nxt;
      }
      writeln(crt.maxElement);
    }
  } catch (EOFException e) {
  }
}