package main

import (
	"fmt"
	"math"
	"sort"
)

type VaultInfo struct {
	chars int
	nums  int
}

func main() {
	var R int
	fmt.Scan(&R)

	var V int
	fmt.Scan(&V)

	VI := make([]VaultInfo, V)
	for i := 0; i < V; i++ {
		fmt.Scan(&VI[i].chars, &VI[i].nums)
	}

	fmt.Println(BankRobber(R, V, VI))
}

func BankRobber(robbers, vaults int, vi []VaultInfo) int {
	robtime := make([]int, robbers)
	for i := 0; i < vaults; i++ {
		//10 numbers, and 5 vowels
		time := int(math.Pow(10, float64(vi[i].nums)) * math.Pow(5, float64(vi[i].chars-vi[i].nums)))

		robtime[0] += time
		sort.Ints(robtime)
	}
	return robtime[robbers-1]
}