Teresa retired from the railroad after $40$ years of service at age $72$ to $2023.$ She received the form rrb$-1099$ below showing for tier $1$ benefits. She also received a form rrb$-1099$r with in box$7$ and reports it on line $5$b of her form $1040/1040$sr$.$ She did not receive any other income. up to $\_\_\_\_\_$ of her tier$1$ benefits may be taxable.