#include <stdio.h>
#include <stdlib.h>

int main(void)
{
    FILE *fin, *fout;
    fin = fopen("matrix.in", "rb");
    fout = fopen("trace.out", "wb");
    unsigned char d1 = '0', d2 = '0', d3 = '0', d4 = '0';
    int numb, cur;
    long long answer = 0;
    fread(&d1, 1, 1, fin);
    fread(&d2, 1, 1, fin);
    numb = d2 + (d1 << 8);
    for (int i = 0; i < numb; ++i)
    {
        for (int j = 0; j < numb; ++j)
        {
            fread(&d1, 1, 1, fin);
            fread(&d2, 1, 1, fin);
            fread(&d3, 1, 1, fin);
            fread(&d4, 1, 1, fin);
            if (i == j)
            {
                cur = d4 + (d3 << 8) + (d2 << 16) + (d3 << 24);
                answer += (long long) cur;
            }
        }
    }
    char temp;
    for (int i = 0; i < 8; ++i)
    {
        temp = (((unsigned long long)answer << (i * 8)) >> 56);
        fwrite(&temp, 1, 1, fout);
    }
    fclose(fin);
    fclose(fout);
    return 0;
}