#include <iostream>
#include <stdio.h>
#include <cmath>
#include <algorithm>
#include <string>
#include <unordered_map>
#include <map>
#include <set>
#include <vector>
using namespace std;
typedef long long int lld;
int n; lld A[104];
// std::unordered_map<lld,lld> S[2];
std::vector<int> V[2];
std::unordered_map<lld,lld> C;
// std::unordered_set<string> E[2];
/*
pair<string,lld> dat(lld& a, lld& b, lld& c) {
std::vector<lld> v={a,b,c};
std::set<lld> tmpS={};
for (lld vv : v) { tmpS.insert(vv); }
string sk="";
for (lld vv : tmpS) { sk+=to_string(vv)+"-"; }
return {sk,tmpS.size()};
}*/
int ss(lld& a, lld& b, lld& c, int d) {
if (d) { return a*(b+c); }
return a*b+c;
}
void in_V(lld a, lld b, lld c, int d, int si) {
// pair<string,lld> dd = dat(a,b,c);
//if (E[si].find(dd.first)==E[si].end()) {
//E[si].insert(dd.first);
//printf("-> %lld %lld %lld: %d\n",a,b,c,d);
/*
std::set<lld> poss={};
poss.insert(ss(a,b,c,d));
poss.insert(ss(a,c,b,d));
poss.insert(ss(b,a,c,d));
poss.insert(ss(b,c,a,d));
poss.insert(ss(c,a,b,d));
poss.insert(ss(c,b,a,d));
for (lld curss : poss) {
S[si][curss]++;
}*/
// guessing game!
if (d) {
if (a) {
V[si].push_back(ss(a,b,c,d));
V[si].push_back(ss(a,c,b,d));
// S[si][ss(a,b,c,d)]++;
// S[si][ss(a,c,b,d)]++;
}
if (b) {
V[si].push_back(ss(b,a,c,d));
V[si].push_back(ss(b,c,a,d));
// S[si][ss(b,a,c,d)]++;
// S[si][ss(b,c,a,d)]++;
}
if (c) {
V[si].push_back(ss(c,a,b,d));
V[si].push_back(ss(c,b,a,d));
}
}
else {
V[si].push_back(ss(a,b,c,d));
V[si].push_back(ss(a,c,b,d));
V[si].push_back(ss(b,a,c,d));
V[si].push_back(ss(b,c,a,d));
V[si].push_back(ss(c,a,b,d));
V[si].push_back(ss(c,b,a,d));
/*
S[si][ss(a,b,c,d)]++;
S[si][ss(a,c,b,d)]++;
S[si][ss(b,a,c,d)]++;
S[si][ss(b,c,a,d)]++;
S[si][ss(c,a,b,d)]++;
S[si][ss(c,b,a,d)]++;
*/
}
// many different meaning, trying to guess the approach.
/*
switch (dd.second) {
case(1): { S[si][ss(a,b,c,d)]++; break; }
case(2): {
std::vector<lld> v={a,b,c};
std::sort(v.begin(),v.end());
if (v[0]==v[1]) { a=v[0];b=v[1];c=v[2]; }
else { a=v[1];b=v[2];c=v[0]; }
S[si][ss(a,b,c,d)]++;
S[si][ss(a,c,b,d)]++;
S[si][ss(c,a,b,d)]++;
break;
}
case(3): {
S[si][ss(a,b,c,d)]++;
S[si][ss(a,c,b,d)]++;
S[si][ss(b,a,c,d)]++;
S[si][ss(b,c,a,d)]++;
S[si][ss(c,a,b,d)]++;
S[si][ss(c,b,a,d)]++;
break; }
default: { break; }
}*/
//}
return;
}
int main() {
scanf("%d",&n); for (int i=0; i<n; i++) { scanf("%lld",&A[i]); }
for (int i=0; i<n; i++) {
for (int j=0; j<n; j++) {
for (int k=0; k<n; k++) {
V[0].push_back(ss(A[i],A[j],A[k],0));
if (A[i]!=0) {
V[1].push_back(ss(A[i],A[j],A[k],1));
}
//in_V(A[i],A[j],A[k],1,1);
//in_V(A[i],A[j],A[k],0,0);
}
}
}
C={};
lld res=0ll;
std::sort(V[0].begin(),V[0].end());
std::sort(V[1].begin(),V[1].end());
for (int& vv : V[0]) {
if (C.count(vv)==0) {
int uu=std::distance(V[1].begin(),std::upper_bound(V[1].begin(),V[1].end(),vv));
int ll=std::distance(V[1].begin(),std::lower_bound(V[1].begin(),V[1].end(),vv));
C[vv]=uu-ll;
}
res+=(lld)C[vv];
}
printf("%lld",res);
return 0;
}
/*
2.38 seconds this time, troll.
1.93 seconds, accepted after minor changes for size of vector array,
exact same idea.
Let's try one more time.
time limit exceeded for this.
the idea is very simple yet requires excessive "guessing" on the ordering of numbers
but it's just not fast enough ha ha ha ha...
*/
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C++ is a widely used middle-level programming language.
When ever you want to perform a set of operations based on a condition If-Else is used.
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You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.
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For loop is used to iterate a set of statements based on a condition.
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return_type function_name(parameters);
function_name (parameters)
return_type function_name(parameters) {
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}