String insertion

Implement an efficient data structure to keep a dynamic array A[0..] of
strings, with two operations:

- ‘I’ s i: Increase the size of A by one (like A.push_back("");). Move
  every string at a position j such that j ≥ i one position to its
  right. Store the string s at the i-th position, which now is empty.

- ‘C’ j: Print the j-th character (0 based) of the whole array,
  considering the concatenation of all its strings from left to right.

Input

Input consists of just one case. Assume that each s has between 1 and 10
lowercase letters, each i is between 0 and the current number of
strings, and each j is between 0 and the current number of characters
minus one. The total number of operations is at most 3 ⋅ 10⁵. An ‘E’
marks the end of the input.

Output

Print a line with the letter at the j-th position for each ‘C’
operation.

Problem information

Author: Salvador Roura

Generation: 2026-01-25T10:11:01.791Z

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