#include<bits/stdc++.h>
using namespace std;

char load[10000];

int main() {
	cin >> load;
	int ans = 0;
	for (int i=0;i<strlen(load);i++) {
		if (int(load[i]) >= 48 && int(load[i]) <= 57) {
			ans += int(load[i])-48;
		}
	}
	printf("%d\n", ans);
}