package main

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

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)

	if !scanner.Scan() {
		return
	}
	n, _ := strconv.Atoi(scanner.Text())

	minOps := 1000000000
	for i := 0; i < n; i++ {
		scanner.Scan()
		a, _ := strconv.Atoi(scanner.Text())
		if a < 0 {
			a = -a
		}
		if a < minOps {
			minOps = a
		}
	}

	fmt.Println(minOps)
}