package main

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

var sc = bufio.NewScanner(os.Stdin)

func readline() string {
	sc.Scan()
	return sc.Text()
}

func find_min(s string) int64 {
	var min int64 = math.MaxInt64
	for i:=2; i<=36; i++ {
		v,e:=strconv.ParseInt(s, i, 64)
		if e == nil && v < min {
			min = v
		}
	}
	return min
}

func main() {
	// input
	num,_ := strconv.Atoi(readline())
	var datum = make([]string, num)
	for i:=0; i<num; i++ {
		datum = append(datum, readline())
	}

	// proc
	var min int64 = math.MaxInt64
	for _,s := range datum {
		if v:=find_min(s); v < min {
			min = v
		}
	}

	// output
	fmt.Println(min)
}