#include <stdio.h>

main() {
    char buf[10000];
    int num = 0;
    scanf("%s", buf);
    
    for (int i=0; i<10000; i++) {
        if (buf[i] == 0)
            break;
        
        if (buf[i] > '0' || buf[i] <= '9') {
            num += buf[i] - '0';
        }
    }
    
    printf("%d\n", num);
}