JS版
let line = parseInt(readline()); const obj = {}; for(let i = 0 ; i<line ; i++){ const arr = readline().split(" "); if(obj.hasOwnProperty(arr[0])) { obj[arr[0]] = Number(obj[arr[0]]) + Number(arr[1]); } else { obj[arr[0]] = arr[1]; } } for([key , value] of Object.entries(obj)){ console.log(key + " " + value); }