#include "bits/stdc++.h"
#define MOD 1000000007
#define INF 11234567890
#define in std::cin
#define out std::cout
#define rep(i,N) for(LL i=0;i<N;++i)
typedef long long int LL;

std::string S;
int ans;

int main()
{
	in >> S;

	rep(i, S.length())
	{
		if ((S[i] - '0') <= 9)
		{
			ans += (S[i] - '0');
		}
	}

	out << ans << std::endl;
	return 0;
}