Pangani​ ​town​ ​at​ ​the​ ​sea​ ​level​ ​has​ ​a​ ​temperature​ ​of​ ​32°C,​ ​what​ ​is​ ​the​ ​temperature​ ​of Ruaha​ ​1500​ ​metres​ ​above​ ​sea​ ​level?