import sys

# sys.setrecursionlimit(200005)
# sys.set_int_max_str_digits(200005)
int1 = lambda x: int(x)-1
pDB = lambda *x: print(*x, end="\n", file=sys.stderr)
p2D = lambda x: print(*x, sep="\n", end="\n\n", file=sys.stderr)
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def SI(): return sys.stdin.readline().rstrip()

dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
# dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
inf = -1-(-1 << 31)
# inf = -1-(-1 << 63)
# md = 10**9+7
md = 998244353

from collections import defaultdict

def pack(arr):
    s = 0
    for a in arr: s = s*21+a
    return s

def unpack(p):
    res = []
    for _ in range(4):
        p, r = divmod(p, 21)
        res.append(r)
    return res[::-1]

def update(c):
    kuro = pkuro[:]
    val = pre[p]
    if c == 0 and kuro[0] < 20:
        kuro[0] += 1
    elif c == 4:
        if kuro[c-1]:
            kuro[c-1] -= 1
            val += 1
    elif kuro[c-1] and kuro[c] < 20:
        kuro[c-1] -= 1
        kuro[c] += 1
    q = pack(kuro)
    if val > dp[q]: dp[q] = val

s = SI()
dp = defaultdict(int)
dp[0] = 0
for c in s:
    c = "KUROI?".find(c)
    if c == -1: continue
    pre, dp = dp, defaultdict(int)
    for p in pre:
        pkuro = unpack(p)
        if c == 5:
            for i in range(5): update(i)
        else:
            update(c)
    # pDB(pre, dp)

print(max(dp.values()))