var input = require("fs").readFileSync("input.txt").toString();
var depths = input.split("\n").filter((a)=>(a)).map((a)=>(a.split(": ").map((b)=>(parseInt(b))))).reduce((dep, a)=>{dep[a[0]] = a[1]; return dep;}, []);
var severity = depths.map((a, i)=>(a*i)).filter((a, i)=>((i % (a/i*2 - 2)) == 0)).reduce((a, b)=>(a+b));
console.log(severity);