S = input().strip()
total_q = S.count('?')

def is_possible(x):
    if x == 0:
        return True
    n = len(S)
    # Check for K positions
    k_pos = []
    used_q_k = 0
    current = 0
    for _ in range(x):
        found = False
        while current < n:
            if S[current] == 'K' or S[current] == '?':
                k_pos.append(current)
                if S[current] == '?':
                    used_q_k += 1
                current += 1
                found = True
                break
            current += 1
        if not found:
            return False
    # Check for U positions
    u_pos = []
    used_q_u = 0
    for k in k_pos:
        current = k + 1
        found = False
        while current < n:
            if S[current] == 'U' or S[current] == '?':
                u_pos.append(current)
                if S[current] == '?':
                    used_q_u += 1
                current += 1
                found = True
                break
            current += 1
        if not found:
            return False
    # Check for R positions
    r_pos = []
    used_q_r = 0
    for u in u_pos:
        current = u + 1
        found = False
        while current < n:
            if S[current] == 'R' or S[current] == '?':
                r_pos.append(current)
                if S[current] == '?':
                    used_q_r += 1
                current += 1
                found = True
                break
            current += 1
        if not found:
            return False
    # Check for O positions
    o_pos = []
    used_q_o = 0
    for r in r_pos:
        current = r + 1
        found = False
        while current < n:
            if S[current] == 'O' or S[current] == '?':
                o_pos.append(current)
                if S[current] == '?':
                    used_q_o += 1
                current += 1
                found = True
                break
            current += 1
        if not found:
            return False
    # Check for I positions
    i_pos = []
    used_q_i = 0
    for o in o_pos:
        current = o + 1
        found = False
        while current < n:
            if S[current] == 'I' or S[current] == '?':
                i_pos.append(current)
                if S[current] == '?':
                    used_q_i += 1
                current += 1
                found = True
                break
            current += 1
        if not found:
            return False
    total_used = used_q_k + used_q_u + used_q_r + used_q_o + used_q_i
    return total_used <= total_q

low = 0
high = len(S) // 5
ans = 0
while low <= high:
    mid = (low + high) // 2
    if is_possible(mid):
        ans = mid
        low = mid + 1
    else:
        high = mid - 1

print(ans)