601 B | 601 chars
import sys
from math import sqrt, pi, sin, factorial
inp = lambda : sys.stdin.readline()[:-1].strip()
mii = lambda x = " " : [*map(int,inp().split(x))]
mfi = lambda x = " " : [*map(float,inp().split(x))]
ii = lambda : int(inp())
fi = lambda : float(inp())
p = print
def solve():
ret = 0
mx, n = mii()
crt = 0
for _ in range(n):
s, a = input().split()
a = int(a)
if s == "leave":
crt -= a
continue
if crt + a <= mx:
crt += a
else:
ret += 1
return ret
if __name__ == "__main__":
tc = 1
for t in range(1, tc+1):
ret = solve()
p(ret)