557 B | 557 chars
import sys
from math import sqrt, pi, sin, factorial
inp = lambda : sys.stdin.readline()[:-1].strip()
mii = lambda x = " " : [*map(int,inp().split(x))]
mfi = lambda x = " " : [*map(float,inp().split(x))]
ii = lambda : int(inp())
fi = lambda : float(inp())
p = print
def solve():
a, b = mii()
_a = a
_b = b
if a > b:
_a -= 1
else:
_b -= 1
for i in range(1, _a + 1):
p(f"{i}:0")
for i in range(1, _b + 1):
p(f"{_a}:{i}")
p(f"{a}:{b}")
if __name__ == "__main__":
tc = 1
for t in range(1, tc+1):
solve()