def main():
    import sys
    K, N = map(int, sys.stdin.readline().split())
    A = list(map(int, sys.stdin.readline().split()))
    B = list(map(int, sys.stdin.readline().split()))
    M = max(B)
    
    if N < K:
        print(A[N])
        return
    
    if any(a >= M for a in A):
        print(M)
        return
    
    current = A.copy()
    max_steps = K * K + K  # Arbitrary large enough steps to detect stabilization
    for i in range(K, max_steps + 1):
        next_val = max(min(current[j], B[j]) for j in range(K))
        if next_val == M:
            print(M)
            return
        current.pop(0)
        current.append(next_val)
        if all(x == current[0] for x in current):
            x = current[0]
            print(x if x <= M else M)
            return
        if i == N:
            print(next_val)
            return
    
    # If not stabilized, which shouldn't happen for the problem's constraints
    print(current[-1])

if __name__ == "__main__":
    main()