#include <stdio.h>
#include <stdlib.h>

int main(void) {
    char S[105];
    int s = 0;

    fgets(S, sizeof(S), stdin);

    for (int i = 0; ; i++) {
        if (S[i] == '\n') {
            break;
        }
        int a = S[i] - '0';
        if (0 <= a && a <= 9) {
            s += a;
        }
    }
    printf("%d\n", s);

    return EXIT_SUCCESS;
}