#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <string.h>

int main(void) {
	int ans = 0;
	char S[10001];

	scanf("%s", &S);
	for (int i = 0; i < strlen(S); i++) {
		if (S[i] == '1')
			ans += 1;
		else if (S[i] == '2')
			ans += 2;
		else if (S[i] == '3')
			ans += 3;
		else if (S[i] == '4')
			ans += 4;
		else if (S[i] == '5')
			ans += 5;
		else if (S[i] == '6')
			ans += 6;
		else if (S[i] == '7')
			ans += 7;
		else if (S[i] == '8')
			ans += 8;
		else if (S[i] == '9')
			ans += 9;
	}
	printf("%d\n", ans);

	return 0;
}