Problem Description

Write a program to grade a test of multiple choice questions. The test has $n$ questions. Each question has a correct answer consisting of up to five uppercase letters from A, B, C, D, and E. If a student answers it correctly then he/she receives $r$ points. If a student answers it incorrectly then he/she receives $-w$ points. If a student does not answers it then he/she receives zero points. Now given $n, \; r, \; w$, the correct answers and the student's answer, please calculate the number of points the student receives. Note that if the student has negative number of points because of the wrong answers, your program should report 0.

Technical Specification and constraints

• $n \le 50$
• $1 \le r \le 50, \; 0 \le w \le r$

• 25pt. The student answers all question and the answers are always in a proper form. That is, They are all in upper cases and sorted, e.g. "ABD", "CD", and "AE".
• 25pt. The student answers all questions but the answer may not be in a proper form. That is, they could have lower case letters but it is always sorted, e.g. "Abd", "cD", and "aE".
• 25pt. The student answers all questions but the answers may not be in a proper form. That is, they could have lower case letters and it is not always sorted, e.g. "bAd", "Dc", and "Ea".
• 25pt. The student may not answer all questions and the answers may not be in a proper form. If the student does not answer a question, he/she will enter "N/A".

Sample Input

5 20 4A B A B C3A B N/A B CA B C B CN/A N/A N/A A B 5 20 4AB ABC BC CD D3AB ABC N/A C CAb abc bc cd DbA bac bc cd c


Sample Output

807603210076