L,R,C=map(int,input().split())
D={}
ans=1000
for x in range(L,R+1):
  d=x*C%1000
  if d==0:
    print(0)
    exit()
  d=1000-d 
  if d not in D:
    D[d]=1
    ans=min(ans,d)
  else:
    break
print(ans)