#include <stdio.h>


int main(void) {
    char s[10010];
    scanf("%s", s);
    int result = 0;
    for (int i = 0; i < 10010; i++) {
        if ('\0' == s[i]) {
            break;
        }
        if ('1' <= s[i] && s[i] <= '9') {
            result += s[i] - '0';
        }
    }
    printf("%d\n", result);
    return 0;
}