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

int main() {

    FILE* oldSkullFile = fopen("oldSkull.final", "rb");
    FILE* newSkullFile = fopen("newSkull.final", "rb");

    unsigned char oldSkull[691];
    unsigned char newSkull[691];

    fread(oldSkull, 1, 691, oldSkullFile);
    fread(newSkull, 1, 691, newSkullFile);

    for (int i = 0; i < 691; ++i)
        if (oldSkull[i] != newSkull[i])
            printf("%c", newSkull[i] - oldSkull[i]);

    puts("");

    return 0;

}