'' if this element is previously seen,  increment count2.
INDENT elif second == arr [ i ] : NEW_LINE count2 += 1 NEW_LINE elif count1 == 0 : NEW_LINE count1 += 1 NEW_LINE DEDENT first = arr [ i ] NEW_LINE INDENT elif count2 == 0 : NEW_LINE count2 += 1 NEW_LINE second = arr [ i ] NEW_LINE DEDENT