SOURCE

var input = '4323123 123'
var a = input.split(' ')
var x = a[0].split('')
var y = a[1].split('')
//console.log(x+':'+y)
var result = []
var num = 0
while(y.length>0){
    let temp = []
    for(let i = 0;i<num;i++){
        temp.unshift(0)
    }
    let chengshu = parseInt(y.pop())
    //console.log(chengshu)
    let jinwei = 0
    for(let j = x.length-1;j>-1;j--){
        let o = parseInt(x[j])*chengshu+jinwei

        jinwei = (o-o%10)/10
        temp.unshift(o%10)
        //console.log(temp)
    }
    if(jinwei!=0)temp.unshift(jinwei)
    result.push(temp.reverse())
    num++
}
//console.log(result)
var sum = []
var tp = 0
while(true){
//function kksk(){
    let shit = 0
    //console.log(result.indexOf([]))
    let kksk = 0
    for(key in result){
        let r= result[key].shift()
        if(r===undefined){
            shit++
            continue
        }
        kksk+=r
    }
    kksk+=tp
    //console.log(kksk)
    if(shit==result.length)break
    tp = (kksk-kksk%10)/10
    sum.push(kksk%10)
    //console.log(sum)
    //console.log(result)
}
console.log(sum.reverse().join(''))
//}