import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
import numpy as np

S = read().rstrip().decode()
dp = np.full((21, 21, 21, 21), -100, np.int32)
dp[0, 0, 0, 0] = 0

for x in S:
    newdp = dp.copy()
    if x in 'K?':
        np.maximum(newdp[1:], dp[:-1], out=newdp[1:])
    if x in 'U?':
        np.maximum(newdp[:-1, 1:], dp[1:, :-1], out=newdp[:-1, 1:])
    if x in 'R?':
        np.maximum(newdp[:, :-1, 1:], dp[:, 1:, :-1], out=newdp[:, :-1, 1:])
    if x in 'O?':
        np.maximum(newdp[:, :, :-1, 1:], dp[:, :, 1:, :-1], out=newdp[:, :, :-1, 1:])
    if x in 'I?':
        np.maximum(newdp[:, :, :, :-1], dp[:, :, :, 1:] + 1, out=newdp[:, :, :, :-1])
    dp = newdp

print(dp.max())