{"raw_statement":[{"iden":"problem statement","content":"AtCoder Inc. has decided to lock the door of its office with a $3$\\-digit PIN code.\nThe company has an $N$\\-digit lucky number, $S$. Takahashi, the president, will erase $N-3$ digits from $S$ and concatenate the remaining $3$ digits without changing the order to set the PIN code.\nHow many different PIN codes can he set this way?\nBoth the lucky number and the PIN code may begin with a $0$."},{"iden":"constraints","content":"*   $4 \\leq N \\leq 30000$\n*   $S$ is a string of length $N$ consisting of digits."},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$N$\n$S$"},{"iden":"sample input 1","content":"4\n0224"},{"iden":"sample output 1","content":"3\n\nTakahashi has the following options:\n\n*   Erase the first digit of $S$ and set `224`.\n*   Erase the second digit of $S$ and set `024`.\n*   Erase the third digit of $S$ and set `024`.\n*   Erase the fourth digit of $S$ and set `022`.\n\nThus, he can set three different PIN codes: `022`, `024`, and `224`."},{"iden":"sample input 2","content":"6\n123123"},{"iden":"sample output 2","content":"17"},{"iden":"sample input 3","content":"19\n3141592653589793238"},{"iden":"sample output 3","content":"329"}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}