Parap

#include<fstream>
using namespace std;
ifstream fin("parap.in");
ofstream fout("parap.out");
int n, i, c, nr;

long long fr[1040], sol, val;

int main()
{
    fin>>n;
    for(i=1; i<=n; i++)
    {
        fin>>val;
        nr=0;
        while(val!=0)
        {
            c=val%10;
            c=(1<<c);
            nr=(nr^c);
            val/=10;
        }
        fr[nr]++;
    }
    for(i=0; i<=1023; i++)
        if(fr[i]>=2)
            sol+=1LL*fr[i]*(fr[i]-1)/2;
    fout<<sol;
    return 0;
}