Consider the set of all reduced fractions between 0 and 1 inclusive with denominators less than or equal to N.

Here is the set when N = 5:

0/1 1/5 1/4 1/3 2/5 1/2 3/5 2/3 3/4 4/5 1/1

Write a program that, given an integer N between 1 and 160 inclusive, prints the fractions in order of increasing magnitude.

INPUT FORMAT

Several lines with a single integer N in each line. Process to the end of file.

SAMPLE INPUT

5
5

OUTPUT FORMAT

One fraction per line, sorted in order of magnitude. print a blank line after each testcase.

SAMPLE OUTPUT

0/1
1/5
1/4
1/3
2/5
1/2
3/5
2/3
3/4
4/5
1/1

0/1
1/5
1/4
1/3
2/5
1/2
3/5
2/3
3/4
4/5
1/1

直接枚举分子分母，然后排序输出即可。水题。

#include<stdio.h>
#include<algorithm>

using namespace std;

struct node
{
	int a;
	int b;
	double cur;
};

int gcd(int a,int b)
{
	if(b==0)
		return a;
	else
		return gcd(b,a%b);
}

bool cmp(node a,node b)
{
	return a.cur<b.cur;
}

int main()
{
	int n,i,j,num=0;
	node acm[10000];
	while(scanf("%d",&n)!=EOF)
	{
		num=0;
		for(i=1;i<=n;i++)
		{
			for(j=0;j<=i;j++)
			{
				if(gcd(i,j)==1)
				{
					acm[num].a=j;
					acm[num].b=i;
					acm[num].cur=(j*1.0)/(i*1.0);
					num++;
				}
			}
		}
		sort(acm,acm+num,cmp);
		for(i=0;i<num;i++)
			printf("%d/%d\n",acm[i].a,acm[i].b);
		printf("\n");
	}
	return 0;
}