import sys

# sys.setrecursionlimit(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 << 63)-1
# inf = (1 << 31)-1
md = 10**9+7
# md = 998244353

def pack(ii):
    p = 0
    for i in ii: p = p*m1+i
    return p

def unpack(p):
    ii = [0]*4
    for j in range(4):
        p, i = divmod(p, m1)
        ii[j] = i
    return ii[::-1]

s = []
for c in SI():
    c = "KUROI?".find(c)
    if c == -1: continue
    s.append(c)

m = len(s)//5
m1 = m+1
n = m1**4
dp = [-1]*n
dp[0] = 0

def upd(c):
    np, d = p, 0
    if c == 0:
        if ii[0] != m:
            ii[0] += 1
            np = pack(ii)
            ii[0] -= 1
    elif c == 4:
        if ii[3]:
            ii[3] -= 1
            np = pack(ii)
            ii[3] += 1
            d = 1
    else:
        if ii[c] < m and ii[c-1]:
            ii[c] += 1
            ii[c-1] -= 1
            np = pack(ii)
            ii[c] -= 1
            ii[c-1] += 1
    ndp[np] = max(ndp[np], dp[p]+d)

for c in s:
    ndp = [-1]*n
    for p in range(n):
        if dp[p] == -1: continue
        ii = unpack(p)
        if c == 5:
            for a in range(5): upd(a)
        else:
            upd(c)
    dp = ndp

print(max(dp))