package main

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

var sc = bufio.NewScanner(os.Stdin)

func main() {
	sc.Split(bufio.ScanWords)
	n := nextInt()
	min := uint64(1<<64 - 1)
	for i := 0; i < n; i++ {
		s := nextLine()
		for j := 2; j < 37; j++ {
			v, err := strconv.ParseUint(s, j, 64)
			if err != nil {
				continue
			}
			if v < min {
				min = v
			}
		}
	}
	fmt.Println(min)
}

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

func nextInt() int {
	i, _ := strconv.Atoi(nextLine())
	return i
}