#include <stdio.h>

void main(){
    char str;
    int ans = 0;
    
    while(1){
        str = getchar();
        if(str == '\n'){
            break;
        }else if(str >= '0' && str <= '9'){
            ans += ( (int)str - (int)'0' );
            
        }
    }
    
    printf("%d",ans);
    return 0;
}