package com.company;


import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Collections;

public class Main {



    public static void main(String[] args) throws Exception {

        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));

        ArrayList<Integer> arraylist = new ArrayList<Integer>();

        int maximum;

        int number;



        while(true){
            number = Integer.parseInt(reader.readLine());

            if(number == 0)
                break;
            else
                arraylist.add(number);

        }

        int i = 0;
        int max = arraylist.get(i);

        for(i = 0; i < arraylist.size(); i++){
            if(max < arraylist.get(i))
                max = arraylist.get(i);

        }
        maximum = max;

        System.out.println(maximum);


    }
}