Python Online o'quv markazi ma'lumot guruhi
#c masala
n = int(input())
x = int(input())
y = int(input())
d = 0
if n > x+y:
d = n - (x+y)
elif n == 1 and x == y and x >= 0:
d = 1
print(d)
natijax = []
natijay = []
if n == 0:
# print(0)
print("")
elif n == 1:
# print(1)
# print(f"{x}:{y}")
natijax.append(f"{x}:{y}")
elif n > x+y:
i = 0
while i < n:
if 0 < x or 0 < y:
if x > 0 and i < n:
# print("1:0")
natijax.append("1:0")
x -= 1
i += 1
if y > 0 and i < n:
natijay.append("0:1")
# print("0:1")
y -= 1
i += 1
else:
natijay.append("0:0")
i += 1
elif n <= x+y:
i = 0
if x != 0:
# x -= 1
i += 1
# print(f"{x}:{0}")
if y != 0:
# y -= 1
i += 1
# print(f"{0}:{y}")
while i < n:
if x > 1 and i < n:
# print("1:0")
natijax.append("1:0")
x -= 1
i += 1
if y > 1 and i < n:
natijay.append("0:1")
# print("0:1")
y -= 1
i += 1
if x != 0:
# x -= 1
# u += 1
# print(f"{x}:{0}")
natijax.append(f"{x}:{0}")
if y != 0:
# y -= 1
# u += 1
# print(f"{0}:{y}")
natijay.append(f"{0}:{y}")
natijax.extend(natijay)
if len(natijax) > 0:
for i in natijax:print(i)