#include <cstdio>
#include <vector>
#include <algorithm>

#define rep(i, n) for(int i = 0; i < (n); ++i)

using namespace std;

typedef pair<int, int> P;
typedef pair<P, int> Q;

int n;
vector<Q> s;

int access(const P& p){
	vector<Q>::iterator it = lower_bound(s.begin(), s.end(), Q(p, 0));
	return it != s.end() && it->first == p ? it->second : 0;
}

int main(){
	scanf("%d", &n);
	rep(i, n){
		int x, y, w;
		scanf("%d%d%d", &x, &y, &w);
		s.push_back(Q(P(x, y), w));
	}
	sort(s.begin(), s.end());
	int ans = 0;
	rep(i, n){
		int u = s[i].first.first;
		int v = s[i].first.second;
		int a = access(P(u - 1, v));
		int b = access(P(u - 1, v + 1));
		int c = access(P(u, v));
		int d = access(P(u, v + 1));
		int e = access(P(u + 1, v));
		int f = access(P(u + 1, v + 1));
		ans = max(max(a + b + c + d, c + d + e + f), ans);
	}
	printf("%d / 1\n", ans);
	return 0;
}