The United Cows of Farmer John (UCFJ) are sending a delegation to the International bOvine olympIad (IOI).

There are N

cows participating in delegation selection (1≤N≤2⋅10^5). They are standing in a line, and cow i has breed bi.

The delegation will consist of a contiguous interval of at least three cows - that is, cows l…r for integers l and r satisfying 1≤l<r≤N and r−l≥2. Three of the cows in the chosen interval are marked as delegation leaders. For legal reasons, the two outermost cows of the chosen interval must be leaders. Moreover, to avoid intra-breed conflict, every leader must be of a different breed from the rest of the delegation (leaders or not).

Help the UCFJ determine (for tax reasons) the number of ways they might choose a delegation to send to the IOI. Two delegations are considered different if they have different members or different leaders.

#5771 upload 5 done 1 how_to_reg 1

United Cows of Farmer John timer 1.5s memory 512MB

#5771

United Cows of Farmer John 1.5s 512MB