#include <fstream.h>

using namespace std;

int main (int argc, char const* argv[])
{
    int n, current, sum=0;
    ifstream in("cifra.in");
    ofstream out("cifra.out");
    in>>n;

    for (unsigned int i = 0; i < n; i += 1)
    {
        in>>current;
        sum+=current*current;
        out<<sum%10;
    }
    return 0;
}