{"raw_statement":[{"iden":"problem statement","content":"There are $N$ integers, $A_1, A_2, ..., A_N$, arranged in a row in this order.\nYou can perform the following operation on this integer sequence any number of times:\n**Operation**: Choose an integer $i$ satisfying $1 \\leq i \\leq N-1$. Multiply both $A_i$ and $A_{i+1}$ by $-1$.\nLet $B_1, B_2, ..., B_N$ be the integer sequence after your operations.\nFind the maximum possible value of $B_1 + B_2 + ... + B_N$."},{"iden":"constraints","content":"*   All values in input are integers.\n*   $2 \\leq N \\leq 10^5$\n*   $-10^9 \\leq A_i \\leq 10^9$"},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$N$\n$A_1$ $A_2$ $...$ $A_N$"},{"iden":"sample input 1","content":"3\n-10 5 -4"},{"iden":"sample output 1","content":"19\n\nIf we perform the operation as follows:\n\n*   Choose $1$ as $i$, which changes the sequence to $10, -5, -4$.\n*   Choose $2$ as $i$, which changes the sequence to $10, 5, 4$.\n\nwe have $B_1 = 10, B_2 = 5, B_3 = 4$. The sum here, $B_1 + B_2 + B_3 = 10 + 5 + 4 = 19$, is the maximum possible result."},{"iden":"sample input 2","content":"5\n10 -4 -8 -11 3"},{"iden":"sample output 2","content":"30"},{"iden":"sample input 3","content":"11\n-1000000000 1000000000 -1000000000 1000000000 -1000000000 0 1000000000 -1000000000 1000000000 -1000000000 1000000000"},{"iden":"sample output 3","content":"10000000000\n\nThe output may not fit into a $32$\\-bit integer type."}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}