{"raw_statement":[{"iden":"problem statement","content":"If there is an integer not less than $0$ satisfying the following conditions, print the smallest such integer; otherwise, print `-1`.\n\n*   The integer has exactly $N$ digits in base ten. (We assume $0$ to be a $1$\\-digit integer. For other integers, leading zeros are not allowed.)\n*   The $s_i$\\-th digit from the left is $c_i$. $\\left(i = 1, 2, \\cdots, M\\right)$"},{"iden":"constraints","content":"*   All values in input are integers.\n*   $1 \\leq N \\leq 3$\n*   $0 \\leq M \\leq 5$\n*   $1 \\leq s_i \\leq N$\n*   $0 \\leq c_i \\leq 9$"},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$N$ $M$\n$s_1$ $c_1$\n$\\vdots$\n$s_M$ $c_M$"},{"iden":"sample input 1","content":"3 3\n1 7\n3 2\n1 7"},{"iden":"sample output 1","content":"702\n\n$702$ satisfies the conditions - its $1$\\-st and $3$\\-rd digits are `7` and `2`, respectively - while no non-negative integer less than $702$ satisfies them."},{"iden":"sample input 2","content":"3 2\n2 1\n2 3"},{"iden":"sample output 2","content":"\\-1"},{"iden":"sample input 3","content":"3 1\n1 0"},{"iden":"sample output 3","content":"\\-1"}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}