function timeConversion(s: string): string { // 07:05:45PM
    const isPM = s.endsWith('PM')
    let hh = Number(s.slice(0,2))
    
    if (isPM && hh < 12) { // handle 0-11 hour in PM 
        hh = hh + 12
    } else if (!isPM && hh === 12) { // handle AM hh === 12 cases
        hh = 0
    } 
    const retrunTime = (hh <= 9 ? '0' : '') + hh.toString() + s.slice(2,8) // 19:05:45
    return retrunTime
}