#include <stdio.h>

int main()
{
        char S[10000+1];
        int sum;

        scanf( "%s\n", S );

        sum = 0;
        for( int i = 0; S[i] != '\0'; i++ ) {
                if( S[i] >= '0' && S[i] <= '9' ) {
                        sum += S[i] - '0';
                }
        }
        printf("%d\n", sum );

        return 0;
}