```go
package main

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

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

	var t int
	fmt.Fscan(reader, &t)
	for ; t > 0; t-- {
		var n int
		fmt.Fscan(reader, &n)
		var prev int
		fmt.Fscan(reader, &prev)
		minMax := 2000000000
		for i := 1; i < n; i++ {
			var curr int
			fmt.Fscan(reader, &curr)
			mx := prev
			if curr > mx {
				mx = curr
			}
			if mx < minMax {
				minMax = mx
			}
			prev = curr
		}
		fmt.Fprintln(writer, minMax-1)
	}
}
```