백준 [1025]

n, score, p = map(int, input().split())

if n == 0:
  print(1)
else:
  scores = list(map(int, input().split()))
  scores.append(score)
  scores.sort(reverse=True)
  idx = scores.index(score)
  # print(scores)
  if n==p and scores[-1] >= score:
    print(-1)
  else:
    print(idx+1)