import sys

sys.setrecursionlimit(10 ** 8)

input = sys.stdin.readline


def main():
    A, B = [int(x) for x in input().split()]

    C = min(A, B)
    D = max(A, B)
    print(min(D - 1, C) * 2)




if __name__ == '__main__':
    main()