package main

import (
	"fmt"
	"math"
	"strconv"
)

func parseX(s string) int64 {
	for i := 2; i <= 36; i++ {
		x, e := strconv.ParseInt(s, i, 64)
		if e == nil {
			return x
		}
	}
	panic("do not reach here")
}

func main() {
	var N int
	var s string
	fmt.Scan(&N)
	z := int64(math.MaxInt64)
	for i := 0; i < N; i++ {
		fmt.Scan(&s)
		x := parseX(s)
		if x < z {
			z = x
		}
	}
	fmt.Println(z)
}