package main

import (
	"bufio"
	"fmt"
	"os"
)

func main() {
	in := bufio.NewReaderSize(os.Stdin, 1<<20)
	out := bufio.NewWriterSize(os.Stdout, 1<<20)
	defer out.Flush()

	var t int
	fmt.Fscan(in, &t)
	for ; t > 0; t-- {
		var n int
		fmt.Fscan(in, &n)
		ans := make([]int, n)
		cur := 0
		for i := 0; i < n; i++ {
			var l, r int
			fmt.Fscan(in, &l, &r)
			if cur < l {
				cur = l
			}
			if cur <= r {
				ans[i] = cur
				cur++
			} else {
				ans[i] = 0
			}
		}
		for i, v := range ans {
			if i > 0 {
				fmt.Fprint(out, " ")
			}
			fmt.Fprint(out, v)
		}
		fmt.Fprintln(out)
	}
}