public class Solution {
    public static void main(String[] args) throws Exception {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        String A = reader.readLine(); int a = Integer.parseInt(A);
        String B = reader.readLine(); int b = Integer.parseInt(B);
        String C = reader.readLine(); int c = Integer.parseInt(C);
        String D = reader.readLine(); int d = Integer.parseInt(D);
        if(a>=b && a>=c && a>=d){System.out.println(a);}
        else if(c>=a && c>=b && c>=d){ System.out.println(c); }
        else if(d>=a && d>=b && d>=c){ System.out.println(d); }
        //напишите тут ваш код
    }
}