import java.util.Scanner;

public class task1 {

public static void main(String[] args) {

Scanner sc = new Scanner(System.in);

String n = sc.nextLine();

//32481 81 + 32

Long ret = Long.MIN_VALUE;

Long[] data = new Long[n.length()-1];

for (int i = 0; i < n.length()-1; i++) {

data[i] = Long.parseLong(n.substring(i,i+2));

}

Long overLappingValue = data[0];

//간격중에 큰 값을 max값으로 선택한다.

Long[] sub_ret = new Long[data.length];

for (int i = 0; i < data.length-1; i++) {

//만약 ret보다 data[i]가크면 업데이트

if(overLappingValue < data[i]) {

overLappingValue = data[i];

}

sub_ret[i] = overLappingValue;

}

for (int i = 0; i < data.length; i++) {

System.out.println(data[i]);

}

long ret2 = Long.MIN_VALUE;

for(int i=2; i<sub_ret.length; i++) {

long left = sub_ret[i-2];

long right = data[i];

ret2 = Math.max(ret2, left+right);

}

System.out.println(ret2);

}

}