#include <iostream>
#include <vector>

using lint = long long;

void solve() {
    int n;
    std::cin >> n;

    lint l, r;
    for (int i = 0; i < n; ++i) {
        lint x;
        std::cin >> x;
        if (i == 0) l = x;
        if (i == n - 1) r = x;
    }

    std::cout << r << "/" << l << std::endl;
}

int main() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    solve();

    return 0;
}