from itertools import product


def solve():
    SS = input()
    S = [c for c in SS if c in 'KUROI?']
    L1 = len(S)
    L2 = L1 // 5 + 1

    dp = [[[[[-1 for o in range(L2)] for r in range(L2)] for u in range(L2)] for k in range(L2)] for x in range(L1 + 1)]
    # dp[x][k][u][r][o] = 次に見るのが x 文字目で、 kまで: k個、uまで: u個、rまで: r個、oまで: o個 のとき、i までできた数
    dp[0][0][0][0][0] = 0
    ma = 0

    for x, c in enumerate(S):
        dpx = dp[x]
        for k, u, r, o in product(range(L2), repeat=4):
            if dpx[k][u][r][o] < 0:
                continue
            now = dpx[k][u][r][o]
            dpy = dp[x + 1]

            if (c == 'K' or c == '?') and k < 20:
                dpy[k + 1][u][r][o] = max(dpy[k + 1][u][r][o], now)
            if (c == 'U' or c == '?') and u < 20 and k:
                dpy[k - 1][u + 1][r][o] = max(dpy[k - 1][u + 1][r][o], now)
            if (c == 'R' or c == '?') and r < 20 and u:
                dpy[k][u - 1][r + 1][o] = max(dpy[k][u - 1][r + 1][o], now)
            if (c == 'O' or c == '?') and o < 20 and r:
                dpy[k][u][r - 1][o + 1] = max(dpy[k][u][r - 1][o + 1], now)
            if (c == 'I' or c == '?') and o:
                dpy[k][u][r][o - 1] = max(dpy[k][u][r][o - 1], now + 1)
                ma = max(ma, now + 1)
    print(ma)


if __name__ == '__main__':
    solve()