#include <stdio.h>
int main(void){
    char S[10001];
    int i = 0, t = 0;
    scanf("%s", S);
    while(S[i] != '\0'){
        if(S[i] >= '0' && S[i] <= '9'){
            t += (S[i] - 48);
        }
        i++;
    }
    printf("%d\n", t);
    return 0;
}