Left Hand Limit Greatest Integer Function

Let [t] denote the greatest integer ≤t and {t} denote the fractional part of t. The integral value of α for which the left hand limit of the function
f(x)=[1+x]+‌

α2[x]+{x}+[x]−1

2[x]+{x}

at x=0 is equal to α−‌

4

3

, is____