运用object[key]相加值
let num = readline()
let line = ''
let arr = []
while( line = readline()){
arr.push(line)
}
let tar = {}
for (let i = 0; i < arr.length; i++) {
const element = arr[i];
let childArr = element.split(' ')
let key = childArr[0]
let value = parseInt(childArr[1])
if(tar[key]){
tar[key] += value
}else {
tar[key] = value
}
}
tar = tar.sort(function(a,b){ return a-b})
for (const key in tar) {
if (Object.hasOwnProperty.call(tar, key)) {
const element = tar[key];
print(key + " " + element)
}
}