#include <stdio.h>
#include <stdlib.h>
int gcd(unsigned a, unsigned b) {
    for (unsigned i = max(a, b); i >= 1; i--)
        if ((a % i == 0) && (b % i == 0))
            return i;
}

int main() {
    unsigned n, nSatisfy = 0;
    scanf("%u", &n);
    for (unsigned a = 1; a <= n; a++)
        for (unsigned b = a; b <= n; b++)
            if (gcd(a, b) == (a ^ b))
                nSatisfy++;
    printf("%u", nSatisfy);
    return 0;
}

/sandbox/1/a.c:5:23: warning: implicit declaration of function 'max' is invalid in C99 [-Wimplicit-function-declaration]
    for (unsigned i = max(a, b); i >= 1; i--)
                      ^
/sandbox/1/a.c:8:1: warning: non-void function does not return a value in all control paths [-Wreturn-type]
}
^
2 warnings generated.
/usr/bin/ld: /tmp/a-0db957.o: in function `gcd':
a.c:(.text+0xe): undefined reference to `max'
/usr/bin/ld: /tmp/a-0db957.o: in function `main':
a.c:(.text+0xb5): undefined reference to `max'
clang: error: linker command failed with exit code 1 (use -v to see invocation)