#include <stdio.h>
int main(){
    //input
    char S[10001];
    scanf("%s",S);

    //calculation
    int total = 0;
    for (int i = 0;i < 10001;i++){
        if (S[i] != '\0'){
            if (S[i] >= 49 && S[i] <= 57){
                total += S[i]-'0';
            }
        }else{
            break;
        }
    }

    //output
    printf("%d\n",total);
    return 0;
}