import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

class No289 {
	public static void main(String[] args) throws IOException{
		
     	BufferedReader br = new BufferedReader((new InputStreamReader(System.in)));
	    char[] chr= br.readLine().toCharArray();  //toCharArray()はString型からchar型の配列にできる
     	
	    int sum = 0;
	    for (int i = 0; i< chr.length; i++){
	    	
	    	/*Character.isDigit(chr)でchrが数値かチェック*/
	    	
     		if (Character.isDigit(chr[i])){
     			
     			/*CharacterクラスのgetNumericVakue(char)でchar型をint型に変換*/
     			
     			sum += Character.getNumericValue(chr[i]); 
     		}
     	}
	    
	    System.out.println(sum);
	}
}