Buggy python submission (verdict: Time Limit Exceeded):
n, a, b, c = map(int, input().split())
mod = 10 ** 9 + 7

def extgcd(a,b):
    r = [1,0,a]
    w = [0,1,b]
    while w[2]!=1:
        q = r[2]//w[2]
        r2 = w
        w2 = [r[0]-q*w[0],r[1]-q*w[1],r[2]-q*w[2]]
        r = r2
        w = w2
    return [w[0],w[1]]

def mod_inv(a,m):
    x = extgcd(a,m)[0]
    return (m+x%m)%m

an = n
bn = n
for i in range(n):
    an *= a
    an *= (a + b)
    an %= mod
    bn *= b
    bn *= (a + b)
    bn %= mod
sum_a = an
sum_b = bn
for i in range(1, n):
    an *= (n + i)
    an *= mod_inv(i, mod)
    an *= b
    an *= mod_inv(a + b, mod)
    an %= mod
    bn *= (n + i)
    bn *= mod_inv(i, mod)
    bn *= a * mod_inv(a + b, mod)
    bn %= mod
    sum_a += an
    sum_a %= mod
    sum_b += bn
    sum_b %= mod
total = (sum_a + sum_b) * 100
q = 1
for i in range(2 * n):
    q *= (a + b)
    q %= mod
q *= (100 - c)
print(total * mod_inv(q, mod) % mod)

Fixed submission:
n, a, b, c = map(int, input().split())
mod = 10 ** 9 + 7

def extgcd(a,b):
    r = [1,0,a]
    w = [0,1,b]
    while w[2]!=1:
        q = r[2]//w[2]
        r2 = w
        w2 = [r[0]-q*w[0],r[1]-q*w[1],r[2]-q*w[2]]
        r = r2
        w = w2
    return [w[0],w[1]]

def mod_inv(a,m):
    x = extgcd(a,m)[0]
    return (m+x%m)%m

an = n
bn = n
for i in range(n):
    an *= a
    an *= (a + b)
    an %= mod
    bn *= b
    bn *= (a + b)
    bn %= mod
sum_a = an
sum_b = bn
inv_ab = mod_inv(a + b, mod)
for i in range(1, n):
    an *= (n + i)
    an *= mod_inv(i, mod)
    an *= b
    an *= inv_ab
    an %= mod
    bn *= (n + i)
    bn *= mod_inv(i, mod)
    bn *= a
    bn *= inv_ab
    bn %= mod
    sum_a += an
    sum_b += bn
total = (sum_a + sum_b) * 100
q = 1
for i in range(2 * n):
    q *= (a + b)
    q %= mod
q *= (100 - c)
print(total * mod_inv(q, mod) % mod)

Buggy python submission (verdict: Time Limit Exceeded):
n, a, b, c = map(int, input().split())
mod = 10 ** 9 + 7

def extgcd(a,b):
    r = [1,0,a]
    w = [0,1,b]
    while w[2]!=1:
        q = r[2]//w[2]
        r2 = w
        w2 = [r[0]-q*w[0],r[1]-q*w[1],r[2]-q*w[2]]
        r = r2
        w = w2
    return [w[0],w[1]]

def mod_inv(a,m):
    x = extgcd(a,m)[0]
    return (m+x%m)%m

an = n
bn = n
for i in range(n):
    an *= a
    an *= (a + b)
    an %= mod
    bn *= b
    bn *= (a + b)
    bn %= mod
sum_a = an
sum_b = bn
for i in range(1, n):
    an *= (n + i)
    an *= mod_inv(i, mod)
    an *= b
    an *= mod_inv(a + b, mod)
    an %= mod
    bn *= (n + i)
    bn *= mod_inv(i, mod)
    bn *= a * mod_inv(a + b, mod)
    bn %= mod
    sum_a += an
    sum_b += bn
total = (sum_a + sum_b) * 100
q = 1
for i in range(2 * n):
    q *= (a + b)
    q %= mod
q *= (100 - c)
print(total * mod_inv(q, mod) % mod)

Fixed submission:
n, a, b, c = map(int, input().split())
mod = 10 ** 9 + 7

def extgcd(a,b):
    r = [1,0,a]
    w = [0,1,b]
    while w[2]!=1:
        q = r[2]//w[2]
        r2 = w
        w2 = [r[0]-q*w[0],r[1]-q*w[1],r[2]-q*w[2]]
        r = r2
        w = w2
    return [w[0],w[1]]

def mod_inv(a,m):
    x = extgcd(a,m)[0]
    return (m+x%m)%m

an = n
bn = n
for i in range(n):
    an *= a
    an *= (a + b)
    an %= mod
    bn *= b
    bn *= (a + b)
    bn %= mod
sum_a = an
sum_b = bn
inv_ab = mod_inv(a + b, mod)
for i in range(1, n):
    an *= (n + i)
    an *= mod_inv(i, mod)
    an *= b
    an *= inv_ab
    an %= mod
    bn *= (n + i)
    bn *= mod_inv(i, mod)
    bn *= a
    bn *= inv_ab
    bn %= mod
    sum_a += an
    sum_b += bn
total = (sum_a + sum_b) * 100
q = 1
for i in range(2 * n):
    q *= (a + b)
    q %= mod
q *= (100 - c)
print(total * mod_inv(q, mod) % mod)

Buggy python submission (verdict: Time Limit Exceeded):
n, a, b, c = map(int, input().split())
mod = 10 ** 9 + 7

def extgcd(a,b):
    r = [1,0,a]
    w = [0,1,b]
    while w[2]!=1:
        q = r[2]//w[2]
        r2 = w
        w2 = [r[0]-q*w[0],r[1]-q*w[1],r[2]-q*w[2]]
        r = r2
        w = w2
    return [w[0],w[1]]

def mod_inv(a,m):
    x = extgcd(a,m)[0]
    return (m+x%m)%m

an = n
bn = n
for i in range(n):
    an = an * a % mod
    an = an * (a + b) % mod
    bn = bn * b % mod
    bn = bn * (a + b) % mod
sum_a = an
sum_b = bn
for i in range(1, n):
    an = an * (n + i) % mod
    an = an * mod_inv(i, mod) % mod
    an = an * b % mod
    an = an * mod_inv(a + b, mod) % mod
    bn = bn * (n + i) % mod
    bn = bn * mod_inv(i, mod) % mod
    bn = bn * a % mod
    bn = bn * mod_inv(a + b, mod) % mod
    sum_a += an
    sum_b += bn
total = (sum_a + sum_b) * 100
q = 1
for i in range(2 * n):
    q = q * (a + b) % mod
q *= (100 - c)
print(total * mod_inv(q, mod) % mod)

Fixed submission:
n, a, b, c = map(int, input().split())
mod = 10 ** 9 + 7

def extgcd(a,b):
    r = [1,0,a]
    w = [0,1,b]
    while w[2]!=1:
        q = r[2]//w[2]
        r2 = w
        w2 = [r[0]-q*w[0],r[1]-q*w[1],r[2]-q*w[2]]
        r = r2
        w = w2
    return [w[0],w[1]]

def mod_inv(a,m):
    x = extgcd(a,m)[0]
    return (m+x%m)%m

an = n
bn = n
for i in range(n):
    an *= a
    an *= (a + b)
    an %= mod
    bn *= b
    bn *= (a + b)
    bn %= mod
sum_a = an
sum_b = bn
inv_ab = mod_inv(a + b, mod)
for i in range(1, n):
    an *= (n + i)
    an *= mod_inv(i, mod)
    an *= b
    an *= inv_ab
    an %= mod
    bn *= (n + i)
    bn *= mod_inv(i, mod)
    bn *= a
    bn *= inv_ab
    bn %= mod
    sum_a += an
    sum_b += bn
total = (sum_a + sum_b) * 100
q = 1
for i in range(2 * n):
    q *= (a + b)
    q %= mod
q *= (100 - c)
print(total * mod_inv(q, mod) % mod)

Buggy python submission (verdict: Time Limit Exceeded):
n, a, b, c = map(int, input().split())
mod = 10 ** 9 + 7

def extgcd(a,b):
    r = [1,0,a]
    w = [0,1,b]
    while w[2]!=1:
        q = r[2]//w[2]
        r2 = w
        w2 = [r[0]-q*w[0],r[1]-q*w[1],r[2]-q*w[2]]
        r = r2
        w = w2
    return [w[0],w[1]]

def mod_inv(a,m):
    x = extgcd(a,m)[0]
    return (m+x%m)%m

an = n
bn = n
for i in range(n):
    an = an * a * (a + b) % mod
    bn = bn * b * (a + b) % mod
sum_a = an
sum_b = bn
for i in range(1, n):
    an = an * (n + i) * mod_inv(i, mod) * b * mod_inv(a + b, mod) % mod
    bn = bn * (n + i) * mod_inv(i, mod) * a * mod_inv(a + b, mod) % mod
    sum_a += an
    sum_b += bn
total = (sum_a + sum_b) * 100
q = 1
for i in range(2 * n):
    q = q * (a + b) % mod
q *= (100 - c)
print(total * mod_inv(q, mod) % mod)

Fixed submission:
n, a, b, c = map(int, input().split())
mod = 10 ** 9 + 7

def extgcd(a,b):
    r = [1,0,a]
    w = [0,1,b]
    while w[2]!=1:
        q = r[2]//w[2]
        r2 = w
        w2 = [r[0]-q*w[0],r[1]-q*w[1],r[2]-q*w[2]]
        r = r2
        w = w2
    return [w[0],w[1]]

def mod_inv(a,m):
    x = extgcd(a,m)[0]
    return (m+x%m)%m

an = n
bn = n
for i in range(n):
    an *= a
    an *= (a + b)
    an %= mod
    bn *= b
    bn *= (a + b)
    bn %= mod
sum_a = an
sum_b = bn
inv_ab = mod_inv(a + b, mod)
for i in range(1, n):
    an *= (n + i)
    an *= mod_inv(i, mod)
    an *= b
    an *= inv_ab
    an %= mod
    bn *= (n + i)
    bn *= mod_inv(i, mod)
    bn *= a
    bn *= inv_ab
    bn %= mod
    sum_a += an
    sum_b += bn
total = (sum_a + sum_b) * 100
q = 1
for i in range(2 * n):
    q *= (a + b)
    q %= mod
q *= (100 - c)
print(total * mod_inv(q, mod) % mod)