In a $1-1$ pass floating head type shell and tube heat exchanger, the tubes $($od $=25$ mm; id $=21$ mm$)$ are arranged in a square pitch. The tube pitch is $32$ mm$.$ The thermal conductivity of the shell side fluid is $0\mathrm{.}19$ W$/$m$.$K$,$ and the Nusselt number is $200.$ The shell$-$side heat transfer coefficient $($in W$/$m$2.$K$),$ rounded off to the nearest integer, is