S = raw_input()

KUROI = ["K", "U", "R", "O", "I", "?"]

string = ""

kurolist = [0]*5

ans = 0

for s in S:
    if s in KUROI:
        string += s

for s in string:
    if s == "K":
        kurolist[0] += 1
    elif s == "U":
        if kurolist[0] > 0:
            kurolist[1] += 1
    elif s == "R":
        if kurolist[0] > 0 and kurolist[1]> 0:
            kurolist[2] += 1
    elif s == "O":
        if kurolist[0] > 0 and kurolist[1] > 0 and kurolist[2] > 0:
            kurolist[3] += 1    
    elif s == "I":
        if kurolist[0] > 0 and kurolist[1] > 0 and kurolist[2] > 0 and kurolist[3] > 0:
            kurolist[4] += 1 
    elif s == "?":
        kurolist[kurolist.index(min(kurolist))] += 1
    
    if min(kurolist) > 0:
        ans += 1
        kurolist = [x-1 for x in kurolist]

print ans