#include <stdio.h>
int main(void){
	char S;
	int count = 0;
	
	while( (S = getchar() ) != EOF ){
		//S = getchar();
		if(S == '0'){
			count += 10;
		}else{
			count += (S - 48);
		}
	}
	
	printf("%d\n",count);
	return 0;
}