#include <stdio.h>
#include <stdlib.h>
int main() {
    int l, c, n, i;
    printf("Enter matrix size: ");
    scanf("%d", &n);
    int** m = (int**)malloc(n * sizeof(int*));
    for (l = 0; l < n; ++l) {
        *(m + l) = (int*)malloc(n * sizeof(int));
        for (c = 0; c < n; ++c) {
            printf("Enter value at line %d, column %d: ", l, c);
            scanf("%d", (*(m + l) + c));
            printf("\n");
        }
    }
    int* u = (int*)malloc(n * n / 4);
    int fc = l = 0;
    for (; l < n; ++l) {
        for (c = 0; c < n; ++c) {
            for (i = 0; i < fc; ++i)
                if (*(u + i) == *(*(m + l) + c)) break;
            *(u + fc++) = *(*(m + l) + c);
            if (fc == n * n / 4) l = c = n;
        }
    }
    free(m);
    m = (int**)malloc((n /= 2) * sizeof(int*));
    *m = (int*)malloc(n * sizeof(int));
    for (l = c = i = 0; i < n * n; ++i) {
        *(*(m + c) + l) = *(u + i);
        printf("%3d ", *(*(m + c) + l));
        if (++l != n) continue;
        *(m + ++c) = (int*)malloc(n * sizeof(int));
        l = 0;
        printf("\n");
    }
}