959 B | 959 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 g(a):
s1, e1 = a.split("-")
x = [*map(int, s1.split(":"))]
y = [*map(int, e1.split(":"))]
return [x[0] * 60 + x[1], y[0] * 60 + y[1]]
def f(a, b):
a = g(a)
b = g(b)
if b[1] <= a[0] or a[1] <= b[0]:
return False
return True
def solve():
while 1:
n = ii()
if n == 0:
break
l = [input() for _ in range(n)]
chk = False
for i in range(n):
for j in range(i + 1, n):
if f(l[i], l[j]):
print("conflict")
chk = True
break
if chk:
break
else:
print("no conflict")
if __name__ == "__main__":
tc = 1
for t in range(1, tc+1):
solve()