n, h = map(int, input().split())
a = []
for i in range(n):
    s = input().split()
    x = int(s[1])
    if s[0] == 'u':
        a += [x]
    else:
        a += [-x]
t = 0
MN = 0
for i in range(n):
    t += a[i]
    if t < 0:
        MN = min(MN , -t)
t=MN
for I in range (n):
    if t < 0 or t > H: