String insertion P21174

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.