472C - Design Tutorial Make It Nondeterministic - CodeForces Solution

import sys

ins = (tok for tok in sys.stdin.readlines())

n = int(next(ins))

names = []
for _ in range(n):
  names.append(next(ins).split())

order = [int(tok)-1 for tok in next(ins).split()]

f,l = names[order[0]]
if f <= l:
  prev_handle = f
else:
  prev_handle = l

feasible = True
for i in range(1, n):
  f,l = names[order[i]]
  if f <= l:
    first = f
    second = l
  else:
    first = l
    second = f
  
  if prev_handle < first:
    prev_handle = first
  elif prev_handle < second:
    prev_handle = second
  else:
    print("NO")
    feasible = False
    break

if feasible:
  print("YES")