We have a sandglass that runs for X seconds. The sand drops from the upper bulb at a rate of 1 gram per second. That is, the upper bulb initially contains X grams of sand.  How many grams of sand will the upper bulb contains after t seconds?
s=input()
r=""
for i in range(len(s)):
    if i%2==0:
        r+=s[i]
print(r)
x,t=(int(i) for i in input().split())
d=x-t
if d<0:
    d=0
print(d)