import sys

sys.setrecursionlimit(10 ** 8)

input = sys.stdin.readline


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

    ans = 0

    p = -1
    while not (A == 0 and B == 0):
        if p == -1:
            if A > B:
                A -= 1
                p = 0
            else:
                B -= 1
                p = 1
        elif (p == 1 and A > 0) or B == 0:
            A -= 1
            if p == 1:
                ans += 1
            p = 0
        else:
            B -= 1
            if p == 0:
                ans += 1
            p = 1

    print(ans)


if __name__ == '__main__':
    main()