#include <stdio.h>

int main(void)
{
    static char moji[10001];
    int i, j;
    int temp = 0;
    
    scanf("%s", moji);
    
    for (i = 0; moji[i] != '\0'; i++)
    {
    }
    for (j = 0; j <= i; j++)
    {
        if (moji[j] <= '9' && moji[j] >= '0')
        {
            temp += moji[j] - 0x30;
        }
    }
    
    printf("%d\n", temp);
    
    return 0;
}