{"raw_statement":[{"iden":"problem statement","content":"There is an integer sequence $A$ of length $N$ whose values are unknown.\nGiven is an integer sequence $B$ of length $N-1$ which is known to satisfy the following:\n$B_i \\geq \\max(A_i, A_{i+1})$\nFind the maximum possible sum of the elements of $A$."},{"iden":"constraints","content":"*   All values in input are integers.\n*   $2 \\leq N \\leq 100$\n*   $0 \\leq B_i \\leq 10^5$"},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$N$\n$B_1$ $B_2$ $...$ $B_{N-1}$"},{"iden":"sample input 1","content":"3\n2 5"},{"iden":"sample output 1","content":"9\n\n$A$ can be, for example, ( $2$ , $1$ , $5$ ), ( $-1$ , $-2$ , $-3$ ), or ( $2$ , $2$ , $5$ ). Among those candidates, $A$ = ( $2$ , $2$ , $5$ ) has the maximum possible sum."},{"iden":"sample input 2","content":"2\n3"},{"iden":"sample output 2","content":"6"},{"iden":"sample input 3","content":"6\n0 153 10 10 23"},{"iden":"sample output 3","content":"53"}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}