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 $j \ge i$ 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 $3 \cdot 10^5$ . 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