문제 링크 : 근무 시간
const readline = require('readline');
const rl = readline.createInterface({
input: process.stdin,
output: process.stdout
});
let sum = 0
rl.on('line', input => {
let [timeA, timeB] = input.split(' ').map(el => el.split(':'))
sum += (+timeB[0]*60 + +timeB[1]) - (+timeA[0]*60 + +timeA[1])
})
rl.on('close', () => {
console.log(sum)
})