{"raw_statement":[{"iden":"problem statement","content":"There are $N$ stones, numbered $1, 2, \\ldots, N$. For each $i$ ($1 \\leq i \\leq N$), the height of Stone $i$ is $h_i$.\nThere is a frog who is initially on Stone $1$. He will repeat the following action some number of times to reach Stone $N$:\n\n*   If the frog is currently on Stone $i$, jump to one of the following: Stone $i + 1, i + 2, \\ldots, i + K$. Here, a cost of $|h_i - h_j|$ is incurred, where $j$ is the stone to land on.\n\nFind the minimum possible total cost incurred before the frog reaches Stone $N$."},{"iden":"constraints","content":"*   All values in input are integers.\n*   $2 \\leq N \\leq 10^5$\n*   $1 \\leq K \\leq 100$\n*   $1 \\leq h_i \\leq 10^4$"},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$N$ $K$\n$h_1$ $h_2$ $\\ldots$ $h_N$"},{"iden":"sample input 1","content":"5 3\n10 30 40 50 20"},{"iden":"sample output 1","content":"30\n\nIf we follow the path $1$ → $2$ → $5$, the total cost incurred would be $|10 - 30| + |30 - 20| = 30$."},{"iden":"sample input 2","content":"3 1\n10 20 10"},{"iden":"sample output 2","content":"20\n\nIf we follow the path $1$ → $2$ → $3$, the total cost incurred would be $|10 - 20| + |20 - 10| = 20$."},{"iden":"sample input 3","content":"2 100\n10 10"},{"iden":"sample output 3","content":"0\n\nIf we follow the path $1$ → $2$, the total cost incurred would be $|10 - 10| = 0$."},{"iden":"sample input 4","content":"10 4\n40 10 20 70 80 10 20 70 80 60"},{"iden":"sample output 4","content":"40\n\nIf we follow the path $1$ → $4$ → $8$ → $10$, the total cost incurred would be $|40 - 70| + |70 - 70| + |70 - 60| = 40$."}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}