牛客網的ACM模式

var readline = require('readline');
const rl = readline.createInterface({
        input: process.stdin,
        output: process.stdout
});
// 多行的話，下面的回調函數會被多次調用
rl.on('line',function(line){
    let a = line.split(' ')
    let sum = 0
    a.forEach(item=>sum += parseInt(item))
    console.log(sum)
})