Buggy python submission (verdict: Runtime Error):
import sys

# import numpy as np
import math
from fractions import gcd
from collections import deque
import bisect

sys.setrecursionlimit(1000000000000)


def factorial(n):
    w = 10**9 + 7
    table = [1]*(n+1)
    for i in range(1, n+1):
        table[i] = table[i-1]*i % w
    return table


def modinv(a, m):
    b = m
    u = 1
    v = 0

    while b > 0:
        t = a // b
        a -= t * b
        a, b = b, a
        u -= t * v
        u, v = v, u
    u %= m
    if u < 0:
        u += m
    return u


def moddiv(x, y, m=10**9+7):
    y_inv = modinv(y, m)
    return x * y_inv % m


def perm(N1, N2):
    table = factorial(N1+N2)
    s = table[N1+N2]
    a = table[N1]
    b = table[N2]
    return moddiv(moddiv(s, a), b)


def main():
    # map(int, input().split())
    # l = list(map(int, input().split()))

    x, y = map(int, input().split())
    diff = abs(x-y)

    if diff == 0:
        if x % 3 != 0:
            print(0)
            return
        cnt = x // 3
        ret = perm(cnt, cnt)
    else:
        if (min(x, y)-diff) % 3 != 0:
            print(0)
            return
        cnt = (min(x, y) - diff) // 3
        ret = perm(cnt, cnt+diff)

    print(ret)


if __name__ == "__main__":
    main()


Fixed submission:
import sys

# import numpy as np
import math
from fractions import gcd
from collections import deque
import bisect

sys.setrecursionlimit(1000000)


def factorial(n):
    w = 10**9 + 7
    table = [1]*(n+1)
    for i in range(1, n+1):
        table[i] = table[i-1]*i % w
    return table


def modinv(a, m):
    b = m
    u = 1
    v = 0

    while b > 0:
        t = a // b
        a -= t * b
        a, b = b, a
        u -= t * v
        u, v = v, u
    u %= m
    if u < 0:
        u += m
    return u


def moddiv(x, y, m=10**9+7):
    y_inv = modinv(y, m)
    return x * y_inv % m


def perm(N1, N2):
    table = factorial(N1+N2)
    s = table[N1+N2]
    a = table[N1]
    b = table[N2]
    return moddiv(moddiv(s, a), b)


def main():
    # map(int, input().split())
    # l = list(map(int, input().split()))

    x, y = map(int, input().split())
    diff = abs(x-y)

    if diff == 0:
        if x % 3 != 0:
            print(0)
            return
        cnt = x // 3
        ret = perm(cnt, cnt)
    else:
        if (min(x, y)-diff) % 3 != 0 or min(x, y) - diff < 0:
            print(0)
            return
        cnt = (min(x, y) - diff) // 3
        ret = perm(cnt, cnt+diff)

    print(ret)


if __name__ == "__main__":
    main()

Buggy python submission (verdict: Runtime Error):
import sys

# import numpy as np
import math
from fractions import gcd
from collections import deque
import bisect

sys.setrecursionlimit(10000000000000)


def factorial(n):
    w = 10**9 + 7
    table = [1]*(n+1)
    for i in range(1, n+1):
        table[i] = table[i-1]*i % w
    return table


def modinv(a, m):
    b = m
    u = 1
    v = 0

    while b > 0:
        t = a // b
        a -= t * b
        a, b = b, a
        u -= t * v
        u, v = v, u
    u %= m
    if u < 0:
        u += m
    return u


def moddiv(x, y, m=10**9+7):
    y_inv = modinv(y, m)
    return x * y_inv % m


def perm(N1, N2):
    table = factorial(N1+N2)
    s = table[N1+N2]
    a = table[N1]
    b = table[N2]
    return moddiv(moddiv(s, a), b)


def main():
    # map(int, input().split())
    # l = list(map(int, input().split()))

    x, y = map(int, input().split())
    diff = abs(x-y)

    if diff == 0:
        if x % 3 != 0:
            print(0)
            return
        cnt = x // 3
        ret = perm(cnt, cnt)
    else:
        if (min(x, y)-diff) % 3 != 0:
            print(0)
            return
        cnt = (min(x, y) - diff) // 3
        ret = perm(cnt, cnt+diff)

    print(ret)


if __name__ == "__main__":
    main()


Fixed submission:
import sys

# import numpy as np
import math
from fractions import gcd
from collections import deque
import bisect

sys.setrecursionlimit(1000000)


def factorial(n):
    w = 10**9 + 7
    table = [1]*(n+1)
    for i in range(1, n+1):
        table[i] = table[i-1]*i % w
    return table


def modinv(a, m):
    b = m
    u = 1
    v = 0

    while b > 0:
        t = a // b
        a -= t * b
        a, b = b, a
        u -= t * v
        u, v = v, u
    u %= m
    if u < 0:
        u += m
    return u


def moddiv(x, y, m=10**9+7):
    y_inv = modinv(y, m)
    return x * y_inv % m


def perm(N1, N2):
    table = factorial(N1+N2)
    s = table[N1+N2]
    a = table[N1]
    b = table[N2]
    return moddiv(moddiv(s, a), b)


def main():
    # map(int, input().split())
    # l = list(map(int, input().split()))

    x, y = map(int, input().split())
    diff = abs(x-y)

    if diff == 0:
        if x % 3 != 0:
            print(0)
            return
        cnt = x // 3
        ret = perm(cnt, cnt)
    else:
        if (min(x, y)-diff) % 3 != 0 or min(x, y) - diff < 0:
            print(0)
            return
        cnt = (min(x, y) - diff) // 3
        ret = perm(cnt, cnt+diff)

    print(ret)


if __name__ == "__main__":
    main()

Buggy python submission (verdict: Runtime Error):
import sys

# import numpy as np
import math
from fractions import gcd
from collections import deque
import bisect

sys.setrecursionlimit(10**12)


def factorial(n):
    w = 10**9 + 7
    table = [1]*(n+1)
    for i in range(1, n+1):
        table[i] = table[i-1]*i % w
    return table


def modinv(a, m):
    b = m
    u = 1
    v = 0

    while b > 0:
        t = a // b
        a -= t * b
        a, b = b, a
        u -= t * v
        u, v = v, u
    u %= m
    if u < 0:
        u += m
    return u


def moddiv(x, y, m=10**9+7):
    y_inv = modinv(y, m)
    return x * y_inv % m


def perm(N1, N2):
    table = factorial(N1+N2)
    s = table[N1+N2]
    a = table[N1]
    b = table[N2]
    return moddiv(moddiv(s, a), b)


def main():
    # map(int, input().split())
    # l = list(map(int, input().split()))

    x, y = map(int, input().split())
    diff = abs(x-y)

    if diff == 0:
        if x % 3 != 0:
            print(0)
            return
        cnt = x // 3
        ret = perm(cnt, cnt)
    else:
        if (min(x, y)-diff) % 3 != 0:
            print(0)
            return
        cnt = (min(x, y) - diff) // 3
        ret = perm(cnt, cnt+diff)

    print(ret)


if __name__ == "__main__":
    main()


Fixed submission:
import sys

# import numpy as np
import math
from fractions import gcd
from collections import deque
import bisect

sys.setrecursionlimit(1000000)


def factorial(n):
    w = 10**9 + 7
    table = [1]*(n+1)
    for i in range(1, n+1):
        table[i] = table[i-1]*i % w
    return table


def modinv(a, m):
    b = m
    u = 1
    v = 0

    while b > 0:
        t = a // b
        a -= t * b
        a, b = b, a
        u -= t * v
        u, v = v, u
    u %= m
    if u < 0:
        u += m
    return u


def moddiv(x, y, m=10**9+7):
    y_inv = modinv(y, m)
    return x * y_inv % m


def perm(N1, N2):
    table = factorial(N1+N2)
    s = table[N1+N2]
    a = table[N1]
    b = table[N2]
    return moddiv(moddiv(s, a), b)


def main():
    # map(int, input().split())
    # l = list(map(int, input().split()))

    x, y = map(int, input().split())
    diff = abs(x-y)

    if diff == 0:
        if x % 3 != 0:
            print(0)
            return
        cnt = x // 3
        ret = perm(cnt, cnt)
    else:
        if (min(x, y)-diff) % 3 != 0 or min(x, y) - diff < 0:
            print(0)
            return
        cnt = (min(x, y) - diff) // 3
        ret = perm(cnt, cnt+diff)

    print(ret)


if __name__ == "__main__":
    main()

Buggy python submission (verdict: Runtime Error):
import sys

# import numpy as np
import math
from fractions import gcd
from collections import deque
import bisect

sys.setrecursionlimit(1000000)


def factorial(n):
    w = 10**9 + 7
    table = [1]*(n+1)
    for i in range(1, n+1):
        table[i] = table[i-1]*i % w
    return table


def modinv(a, m):
    b = m
    u = 1
    v = 0

    while b > 0:
        t = a // b
        a -= t * b
        a, b = b, a
        u -= t * v
        u, v = v, u
    u %= m
    if u < 0:
        u += m
    return u


def moddiv(x, y, m=10**9+7):
    y_inv = modinv(y, m)
    return x * y_inv % m


def perm(N1, N2):
    table = factorial(N1+N2)
    s = table[N1+N2]
    a = table[N1]
    b = table[N2]
    return moddiv(moddiv(s, a), b)


def main():
    # map(int, input().split())
    # l = list(map(int, input().split()))

    x, y = map(int, input().split())
    diff = abs(x-y)

    if diff == 0:
        if x % 3 != 0:
            print(0)
            return
        cnt = x // 3
        ret = perm(cnt, cnt)
    else:
        if (min(x, y)-diff) % 3 != 0:
            print(0)
            return
        cnt = (min(x, y) - diff) // 3
        ret = perm(cnt, cnt+diff)

    print(ret)


if __name__ == "__main__":
    main()


Fixed submission:
import sys

# import numpy as np
import math
from fractions import gcd
from collections import deque
import bisect

sys.setrecursionlimit(1000000)


def factorial(n):
    w = 10**9 + 7
    table = [1]*(n+1)
    for i in range(1, n+1):
        table[i] = table[i-1]*i % w
    return table


def modinv(a, m):
    b = m
    u = 1
    v = 0

    while b > 0:
        t = a // b
        a -= t * b
        a, b = b, a
        u -= t * v
        u, v = v, u
    u %= m
    if u < 0:
        u += m
    return u


def moddiv(x, y, m=10**9+7):
    y_inv = modinv(y, m)
    return x * y_inv % m


def perm(N1, N2):
    table = factorial(N1+N2)
    s = table[N1+N2]
    a = table[N1]
    b = table[N2]
    return moddiv(moddiv(s, a), b)


def main():
    # map(int, input().split())
    # l = list(map(int, input().split()))

    x, y = map(int, input().split())
    diff = abs(x-y)

    if diff == 0:
        if x % 3 != 0:
            print(0)
            return
        cnt = x // 3
        ret = perm(cnt, cnt)
    else:
        if (min(x, y)-diff) % 3 != 0 or min(x, y) - diff < 0:
            print(0)
            return
        cnt = (min(x, y) - diff) // 3
        ret = perm(cnt, cnt+diff)

    print(ret)


if __name__ == "__main__":
    main()

Buggy python submission (verdict: Runtime Error):
import sys

# import numpy as np
import math
from fractions import gcd
from collections import deque
import bisect

sys.setrecursionlimit(10000)


def factorial(n):
    w = 10**9 + 7
    table = [1]*(n+1)
    for i in range(1, n+1):
        table[i] = table[i-1]*i % w
    return table


def modinv(a, m):
    b = m
    u = 1
    v = 0

    while b > 0:
        t = a // b
        a -= t * b
        a, b = b, a
        u -= t * v
        u, v = v, u
    u %= m
    if u < 0:
        u += m
    return u


def moddiv(x, y, m=10**9+7):
    y_inv = modinv(y, m)
    return x * y_inv % m


def perm(N1, N2):
    table = factorial(N1+N2)
    s = table[N1+N2]
    a = table[N1]
    b = table[N2]
    return moddiv(moddiv(s, a), b)


def main():
    # map(int, input().split())
    # l = list(map(int, input().split()))

    x, y = map(int, input().split())
    diff = abs(x-y)

    if diff == 0:
        if x % 3 != 0:
            print(0)
            return
        cnt = x // 3
        ret = perm(cnt, cnt)
    else:
        if (min(x, y)-diff) % 3 != 0:
            print(0)
            return
        cnt = (min(x, y) - diff) // 3
        ret = perm(cnt, cnt+diff)

    print(ret)


if __name__ == "__main__":
    main()


Fixed submission:
import sys

# import numpy as np
import math
from fractions import gcd
from collections import deque
import bisect

sys.setrecursionlimit(1000000)


def factorial(n):
    w = 10**9 + 7
    table = [1]*(n+1)
    for i in range(1, n+1):
        table[i] = table[i-1]*i % w
    return table


def modinv(a, m):
    b = m
    u = 1
    v = 0

    while b > 0:
        t = a // b
        a -= t * b
        a, b = b, a
        u -= t * v
        u, v = v, u
    u %= m
    if u < 0:
        u += m
    return u


def moddiv(x, y, m=10**9+7):
    y_inv = modinv(y, m)
    return x * y_inv % m


def perm(N1, N2):
    table = factorial(N1+N2)
    s = table[N1+N2]
    a = table[N1]
    b = table[N2]
    return moddiv(moddiv(s, a), b)


def main():
    # map(int, input().split())
    # l = list(map(int, input().split()))

    x, y = map(int, input().split())
    diff = abs(x-y)

    if diff == 0:
        if x % 3 != 0:
            print(0)
            return
        cnt = x // 3
        ret = perm(cnt, cnt)
    else:
        if (min(x, y)-diff) % 3 != 0 or min(x, y) - diff < 0:
            print(0)
            return
        cnt = (min(x, y) - diff) // 3
        ret = perm(cnt, cnt+diff)

    print(ret)


if __name__ == "__main__":
    main()

Buggy python submission (verdict: Runtime Error):
import sys

# import numpy as np
import math
from fractions import gcd
from collections import deque
import bisect

sys.setrecursionlimit(10000)


def factorial(n):
    w = 10**9 + 7
    table = [1]*(n+1)
    for i in range(1, n+1):
        table[i] = table[i-1]*i % w
    return table


def modinv(a, m):
    b = m
    u = 1
    v = 0

    while b > 0:
        t = a // b
        a -= t * b
        a, b = b, a
        u -= t * v
        u, v = v, u
    u %= m
    if u < 0:
        u += m
    return u


def moddiv(x, y, m=10**9+7):
    y_inv = modinv(y, m)
    return x * y_inv % m


def perm(N1, N2):
    table = factorial(N1+N2)
    s = table[N1+N2]
    a = table[N1]
    b = table[N2]
    return moddiv(moddiv(s, a), b)


def main():
    # map(int, input().split())
    # l = list(map(int, input().split()))

    x, y = map(int, input().split())
    diff = abs(x-y)

    if diff == 0:
        if x % 3 != 0:
            return
        cnt = x // 3
        ret = perm(cnt, cnt)
    else:
        if (min(x, y)-diff) % 3 != 0:
            return
        cnt = (min(x, y) - diff) // 3
        ret = perm(cnt, cnt+diff)

    print(ret)


if __name__ == "__main__":
    main()


Fixed submission:
import sys

# import numpy as np
import math
from fractions import gcd
from collections import deque
import bisect

sys.setrecursionlimit(1000000)


def factorial(n):
    w = 10**9 + 7
    table = [1]*(n+1)
    for i in range(1, n+1):
        table[i] = table[i-1]*i % w
    return table


def modinv(a, m):
    b = m
    u = 1
    v = 0

    while b > 0:
        t = a // b
        a -= t * b
        a, b = b, a
        u -= t * v
        u, v = v, u
    u %= m
    if u < 0:
        u += m
    return u


def moddiv(x, y, m=10**9+7):
    y_inv = modinv(y, m)
    return x * y_inv % m


def perm(N1, N2):
    table = factorial(N1+N2)
    s = table[N1+N2]
    a = table[N1]
    b = table[N2]
    return moddiv(moddiv(s, a), b)


def main():
    # map(int, input().split())
    # l = list(map(int, input().split()))

    x, y = map(int, input().split())
    diff = abs(x-y)

    if diff == 0:
        if x % 3 != 0:
            print(0)
            return
        cnt = x // 3
        ret = perm(cnt, cnt)
    else:
        if (min(x, y)-diff) % 3 != 0 or min(x, y) - diff < 0:
            print(0)
            return
        cnt = (min(x, y) - diff) // 3
        ret = perm(cnt, cnt+diff)

    print(ret)


if __name__ == "__main__":
    main()