#include <stdio.h>

int main(void)
{
    FILE *finput = fopen("matrix.in", "rb");
    FILE *foutput = fopen("trace.out", "wb");

    short int size;
    int byte, number, step = 1;
    fread(&byte, 1, 1, finput);
    size = byte * 256;
    fread(&byte, 1, 1, finput);
    size += byte;
    long long trace = 0;


    for (int i = 0; i < size; i++)
    {
        for (int j = 0; j < size; j++)
        {
            number = 0;
            for (int h = 0; h < 4; h++)
            {
                fread(&byte, 1, 1, finput);
                number *= 256;
                number += byte;
            }
            if (step % (size+1) == 1)
            {
                trace += number;
            }
            step++;
        }
    }

    fwrite(&trace, sizeof(long long int), 1, foutput);
    fclose(finput);
    fclose(foutput);

    FILE *finput1 = fopen("trace.out", "rb");

    int array[8];
    for (int i = 0; i < 8; i++)
    {
        fread(&array[i], 1, 1, finput1);
    }
    fclose(finput1);
    FILE *finput2 = fopen("trace.out", "wb");
    for (int i = 7; i >= 0; i--)
    {
        fwrite(&array[i], 1, 1, finput2);
    }

    fclose(finput2);

    return 0;
}