def solve(coordinates):

d = dict(coordinates)

y = d.values()
x = d.keys()

min_x = min(x)
max_x = max(x)
min_y = min(y)
max_y = max(y)

ret = "YES"
for el in coordinates:
    if (el[0] > min_x) & (el[0] < max_x) & (el[1] > min_y) & (el[1] < max_y):
        ret = "NO"
        break
return ret