【題目敘述】https://atcoder.jp/contests/abc175/tasks/abc175_b
#include <iostream>
#include <set>
using namespace std;
int n, ans;
long long a[105];
int main() {
cin >> n;
for (int i = 0; i < n; i++){
cin >> a[i];
for (int j = 0; j < i; j++){
if (a[j] == a[i]) continue;
for (int k = 0; k < j; k++){
if (a[k] == a[j] || a[k] == a[i]) continue;
if (a[i] < a[j]+a[k] && a[j] < a[i]+a[k] && a[k] < a[i]+a[j]) ans++;
}
}
}
cout << ans << "\n";
}