{"raw_statement":[{"iden":"problem statement","content":"$N$ programmers are going to participate in the preliminary stage of DDCC 20XX. Due to the size of the venue, however, at most $9$ contestants can participate in the finals.\nThe preliminary stage consists of several rounds, which will take place as follows:\n\n*   All the $N$ contestants will participate in the first round.\n*   When $X$ contestants participate in some round, the number of contestants advancing to the next round will be decided as follows:\n    *   The organizer will choose two consecutive digits in the decimal notation of $X$, and replace them with the sum of these digits. The number resulted will be the number of contestants advancing to the next round.  \n        For example, when $X = 2378$, the number of contestants advancing to the next round will be $578$ (if $2$ and $3$ are chosen), $2108$ (if $3$ and $7$ are chosen), or $2315$ (if $7$ and $8$ are chosen).  \n        When $X = 100$, the number of contestants advancing to the next round will be $10$, no matter which two digits are chosen.\n*   The preliminary stage ends when $9$ or fewer contestants remain.\n\nRingo, the chief organizer, wants to hold as many rounds as possible. Find the maximum possible number of rounds in the preliminary stage.\nSince the number of contestants, $N$, can be enormous, it is given to you as two integer sequences $d_1, \\ldots, d_M$ and $c_1, \\ldots, c_M$, which means the following: the decimal notation of $N$ consists of $c_1 + c_2 + \\ldots + c_M$ digits, whose first $c_1$ digits are all $d_1$, the following $c_2$ digits are all $d_2$, $\\ldots$, and the last $c_M$ digits are all $d_M$."},{"iden":"constraints","content":"*   $1 \\leq M \\leq 200000$\n*   $0 \\leq d_i \\leq 9$\n*   $d_1 \\neq 0$\n*   $d_i \\neq d_{i+1}$\n*   $c_i \\geq 1$\n*   $2 \\leq c_1 + \\ldots + c_M \\leq 10^{15}$"},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$M$\n$d_1$ $c_1$\n$d_2$ $c_2$\n$:$\n$d_M$ $c_M$"},{"iden":"sample input 1","content":"2\n2 2\n9 1"},{"iden":"sample output 1","content":"3\n\nIn this case, $N = 229$ contestants will participate in the first round. One possible progression of the preliminary stage is as follows:\n\n*   $229$ contestants participate in Round $1$, $49$ contestants participate in Round $2$, $13$ contestants participate in Round $3$, and $4$ contestants advance to the finals.\n\nHere, three rounds take place in the preliminary stage, which is the maximum possible number."},{"iden":"sample input 2","content":"3\n1 1\n0 8\n7 1"},{"iden":"sample output 2","content":"9\n\nIn this case, $1000000007$ will participate in the first round."}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}