#include <iostream>
#include <string>
#include <cctype>
#include <algorithm>
int main()
{
std::string s;
std::getline( std::cin, s );
int magic = 0;
std::for_each( s.begin(), s.end(), [&magic](char c)
{
if( std::isdigit(c) ) magic+= (c-'0');
if( magic > 10 ) magic = 1 + magic%10;
} );
std::cout << magic;
std::system( "pause" );
return 0;
}
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