{"raw_statement":[{"iden":"problem statement","content":"We have $N$ fuses connected in series. The $i$\\-th fuse from the left has a length of $A_i$ centimeters and burns at a constant speed of $B_i$ centimeters per second.\nConsider igniting this object from left and right ends simultaneously. Find the distance between the position where the two flames will meet and the left end of the object."},{"iden":"constraints","content":"*   $1 \\leq N \\leq 10^5$\n*   $1 \\leq A_i,B_i \\leq 1000$\n*   All values in input are integers."},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$N$\n$A_1$ $B_1$\n$A_2$ $B_2$\n$\\vdots$\n$A_N$ $B_N$"},{"iden":"sample input 1","content":"3\n1 1\n2 1\n3 1"},{"iden":"sample output 1","content":"3.000000000000000\n\nThe two flames will meet at $3$ centimeters from the left end of the object."},{"iden":"sample input 2","content":"3\n1 3\n2 2\n3 1"},{"iden":"sample output 2","content":"3.833333333333333"},{"iden":"sample input 3","content":"5\n3 9\n1 2\n4 6\n1 5\n5 3"},{"iden":"sample output 3","content":"8.916666666666668"}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}