include <bits/stdc++.h>

using namespace std; const long long mod=1000000007; long long sm(long long n) { long long s=0; while(n>0) { int k=n%10; if(k==2 or k==3 or k==5 or k==7) s+=k; n=n/10; }

return s ; } long long n; int main () { cin>>n; if(sm(n)!=0) cout<<sm(n); else cout<<-1; }