#include <stdio.h>
#include <math.h>

int main(void) {
    int i,j,score,scoreSum,scoreArray[9];
    double power;
    scanf("%d",&score);
    for (i = 0; i < 9; i++) {
        power = pow(10,i);
        scoreArray[i] = (int)(score/power)%10;
    }
    for (j = 0; j < 9; j++) {
        if (scoreArray[j] != 0) {
        scoreSum += scoreArray[j];
        }else {
            scoreSum += 10;
        }
    }
    printf("%d\n",scoreSum);
    return 0;
}