a,b = map(int,input().strip().split())
if a > 1 and b > 1:
    if a >= b:
        ans = b - 1
        ans = ans + b*(a-1)
    else:
        ans = a-1
        ans = ans + a*(b-1)
    print(ans)
elif a == 1 and b == 1:
    print(0)
elif a == 1:
    ans = (b-1)
    print(ans)
elif b == 1:
    ans = (a-1)
    print(ans)