#include<iostream>
using namespace std;
int main()
{
int a;
int b=0;
for(int i=0; i<5; i++)
{
cin>>a;
b+=a*a;
}
cout<<b%10;
}
#include<iostream>
using namespace std;
int main()
{
int a;
int b = 0;
cin >> a;
for (int i = 10000; i >= 1; i /= 10)
{
b += ((a / i) * (a / i));
a %= i;
}
cout << b%10;
}