Problem:
Score: 100 points

Problem Statement

E869120 has A 1-yen coins and infinitely many 500-yen coins.

Determine if he can pay exactly N yen using only these coins.

Constraints

N is an integer between 1 and 10000 (inclusive).

A is an integer between 0 and 1000 (inclusive).

Input

Input is given from Standard Input in the following format:

N
A

Output

If E869120 can pay exactly N yen using only his 1-yen and 500-yen coins, print Yes; otherwise, print No.

Sample Input 1

2018
218

Sample Output 1

Yes

We can pay 2018 yen with four 500-yen coins and 18 1-yen coins, so the answer is Yes.

Sample Input 2

2763
0

Sample Output 2

No

When we have no 1-yen coins, we can only pay a multiple of 500 yen using only 500-yen coins. Since 2763 is not a multiple of 500, we cannot pay this amount.

Sample Input 3

37
514

Sample Output 3

Yes

Solution in Python (3.4.3) (judge verdict: Runtime Error)

H,W = map(int, input().split())
List = [input() for i in range(H)]
queue = [(0,0,1)]
shape = sum(row.count("#") for row in List)
used ={(0,0)}

def check(x,y,c):
    if(x>W-1 or y>H-1 or x<0 or y<0):
        return
    if(List[y][x] == '#'):
        return
    if(x,y) in used:
        return
    queue.append((x,y,c+1))
    used.add((x,y))

f= -1
while queue:
    x,y,c = queue[0]
    if x==W-1 and y==H-1:
        f=1
        break
    queue.pop(0)
    check(x+1,y,c)
    check(x, y+1,c)
    check(x-1,y,c)
    check(x, y-1,c)
print(f if f == -1 else(H*W-c-shape))