#include #include #include using namespace std; const long long MOD = 1000000007LL; vector counts; vector usedIndexes(3, -1); long long patterns(int used, int index) { if (used == 3) { long long result = counts[usedIndexes[0]]; result *= counts[usedIndexes[1]]; result %= MOD; result *= counts[usedIndexes[2]]; result %= MOD; return result; } if (index == counts.size()) { return 0; } int oldUsedIndex = usedIndexes[used]; usedIndexes[used] = index; long long result = patterns(used + 1, index + 1); usedIndexes[used] = oldUsedIndex; result += patterns(used, index + 1); result %= MOD; return result; } int main() { int n; cin >> n; vector a(n); for (int i = 0; i < n; ++i) { cin >> a[i]; } map valueToCount; for (int i = 0; i < n; ++i) { ++valueToCount[a[i]]; } for (map::const_iterator it = valueToCount.begin(); it != valueToCount.end(); ++it) { counts.push_back(it->second); } int m = counts.size(); if (m < 3) { cout << 0 << endl; return 0; } long long result = patterns(0, 0); cout << result << endl; return 0; }