//https://ncode.syosetu.com/n4830bu/280/
#include <bits/stdc++.h>
using namespace std;

int main() {
    int N;
    cin >> N;
    vector<long long> Z(N);
    for (auto&& z : Z) {
        cin >> z;
    }
    cout << Z.back() << "/" << Z[0] << endl;
}