package main import ( "fmt" "sort" ) func main() { var n int fmt.Scan(&n) mapRes := make(map[int]int) for i := 0; i < n; i++ { var key int var value int fmt.Scan(&key, &value) mapRes[key] += value } var keyArr []int for k := range mapRes { keyArr = append(keyArr, k) } sort.Ints(keyArr) for _, v := range keyArr { fmt.Println(v, mapRes[v]) } }