snake_case to camelCase

parts = readline()
let tab = parts.split('_')
let nTab = []
nTab.push(tab[0])
for(let i = 1; i < tab.length; i++)
{
    let str = tab[i]
    if(str.length != 0)
    {
        let nStr = str.toUpperCase()[0] + str.substring(1)
        nTab.push(nStr)
    }

}
console.log(nTab.join(''))