S = list(input())

ans = 0
while True:
    # t
    for i in range(len(S)):
        if S[i] == 't':
            S[i] = 'T'
            break
    else:
        break
    # r
    for i in range(len(S)):
        if S[i] == 'r':
            S[i] = 'R'
            break
    else:
        break
    # e
    for i in range(len(S)):
        if S[i] == 'e':
            S[i] = 'E'
            break
    else:
        break
    # e
    for i in range(len(S)):
        if S[i] == 'e':
            S[i] = 'E'
            ans += 1
            break
    else:
        break

print(ans)