package main

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

func main() {
	in := bufio.NewReader(os.Stdin)
	out := bufio.NewWriter(os.Stdout)
	defer out.Flush()

	var t int
	if _, err := fmt.Fscan(in, &t); err != nil {
		return
	}

	for i := 0; i < t; i++ {
		var n int
		var s string
		fmt.Fscan(in, &n, &s)

		mid := n / 2
		c := s[mid]
		ans := 0

		for j := mid; j >= 0 && s[j] == c; j-- {
			ans++
		}
		for j := mid + 1; j < n && s[j] == c; j++ {
			ans++
		}

		fmt.Fprintln(out, ans)
	}
}