# Read input
import sys
import threading
def main():
import sys
sys.setrecursionlimit(1 << 25)
N, R = map(int, sys.stdin.readline().split())
R0 = int(sys.stdin.readline())
positions = []
for _ in range(2*N -1):
positions.append(int(sys.stdin.readline()))
better_archers_starting_positions = [0] * (2*N -1)
for i in range(2*N -1):
if positions[i] < R0:
better_archers_starting_positions[i] = 1
better_archers_starting_targets = [0] * N
for t in range(N):
pos1 = 2*t
pos2 = 2*t +1
if pos1 < 2*N -1:
better_archers_starting_targets[t] += better_archers_starting_positions[pos1]
if pos2 < 2*N -1:
better_archers_starting_targets[t] += better_archers_starting_positions[pos2]
suffix_sum_better = [0] * (N+1)
for t in range(N-1, -1, -1):
suffix_sum_better[t] = suffix_sum_better[t+1] + better_archers_starting_targets[t]
min_finishing_target = float('inf')
best_t = -1
for t in range(1, N+1):
N_better_right = suffix_sum_better[t]
finishing_target = t + N_better_right
if finishing_target < min_finishing_target:
min_finishing_target = finishing_target
best_t = t
elif finishing_target == min_finishing_target and t > best_t:
best_t = t
print(best_t)
threading.Thread(target=main).start()
