#P11138. APC String Reduction
APC String Reduction
APC String Reduction
You are given a string \(S\) consisting only of the characters A
, P
, and C
. You may repeatedly remove a subsequence \(A P C\) (i.e. there exist indices \(i, j, k\) with \(i < j < k\) and \(S[i]=A,\ S[j]=P,\ S[k]=C\)) from \(S\). Continue removing such subsequences as long as possible.
After no further removals can be made, output the final string. If the string becomes empty, output Perfect
.
The mathematical formulation of the removal step is as follows: if there exist indices \(i, j, k\) such that \[ \exists\, i,j,k:\; i < j < k,\quad S[i]=A,\quad S[j]=P,\quad S[k]=C, \] remove the characters at those positions. The process is repeated until no such triple exists.
inputFormat
The input consists of a single line containing the string \(S\). It is guaranteed that \(S\) only contains the characters A
, P
, and C
.
outputFormat
Output the string after performing the maximal removals. If the resulting string is empty, output Perfect
.
sample
APC
Perfect