#include<bits/stdc++.h>
using namespace std;
int main() {
long long n;cin>>n;
while(n)
{
if(n%10!=0)
break;
n/=10;
}
if(n==0)
{
cout<<0<<endl;
return 0;
}
else if(n>0)
{
int sum = 0;
while(n)
{
sum=sum10+n%10;
n/=10;
}
cout<<sum<<endl;
}
else
{
n=-1n;
int sum=0;
while(n)
{
sum=sum*10+n%10;
n/=10;
}
cout<<"-"<<sum<<endl;
}
return 0;
}
