X = input()
# X = 'SSTTST'
# X = 'TSSTTTSS'

# naive case
# len_prev = -1
# while len_prev != len(X):
#     len_prev = len(X)
#     X = X.replace('ST', '')
# print(len(X))


i = 0
cnt = []
X += " "
cur = 1
for i in range(len(X) - 1):
    if X[i] == X[i + 1]:
        cur += 1
    else:
        cnt.append((X[i], cur))
        cur = 1

total = 0
for i in range(len(cnt) - 1):
    if cnt[i][0] == 'S':
        total += min(cnt[i][1], cnt[i + 1][1])
print(len(X) - 1 - 2 * total)
