#include <stdio.h>

int gcd(int x, int y)
{
	if (x == 0)
		return y;
	else
		return gcd(y%x, x);
}

void imm_left(int numer, int denom, int max_denom, int *nu, int *de)
{
	/* nu/de < numer/denom
	 * => nu < numer*de/denom
	 */
	int res_nu = 0, res_de = 1;
	int i;
	for (i = 2; i <= max_denom; i++) {
		if (i == denom)
			continue;
		int t = numer * i / denom;
		/* t/i > res_nu/res_de */
		if (gcd(t, i) != 1)
			continue;
		if (t * res_de > i * res_nu) {
			res_nu = t;
			res_de = i;
		}
	}
	*nu = res_nu;
	*de = res_de;
}

int main()
{
	int nu, de;
	imm_left(3, 7, 1000000, &nu, &de);
	printf("%d/%d\n", nu, de);
}