{"raw_statement":[{"iden":"problem statement","content":"Takahashi is taking exams on $N$ subjects. The score on each subject will be an integer between $0$ and $K$ (inclusive).\nHe has already taken exams on $N-1$ subjects and scored $A_i$ points on the $i$\\-th subject.\nHis goal is to achieve the average score of $M$ points or above on the $N$ subjects.\nPrint the minimum number of points Takahashi needs on the final subject to achieve his goal.\nIf the goal is unachievable, print `-1` instead."},{"iden":"constraints","content":"*   $2 \\leq N \\leq 100$\n*   $1 \\leq K \\leq 100$\n*   $1 \\leq M \\leq K$\n*   $0 \\leq A_i \\leq K$\n*   All values in input are integers."},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$N$ $K$ $M$\n$A_1$ $A_2$ $...$ $A_{N-1}$"},{"iden":"sample input 1","content":"5 10 7\n8 10 3 6"},{"iden":"sample output 1","content":"8\n\nIf he scores $8$ points on the final subject, his average score will be $(8+10+3+6+8)/5 = 7$ points, which meets the goal."},{"iden":"sample input 2","content":"4 100 60\n100 100 100"},{"iden":"sample output 2","content":"0\n\nScoring $0$ points on the final subject still meets the goal."},{"iden":"sample input 3","content":"4 100 60\n0 0 0"},{"iden":"sample output 3","content":"\\-1\n\nHe can no longer meet the goal."}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}