import Foundation

func readInput(filePath: String) -> ([Int], [Int]) {
    let content =  try? String(contentsOfFile: filePath, encoding: .ascii)
    let lines = content!.split(separator: "\n")
    var leftList: [Int] = []
    var rightList: [Int] = []
    for line in lines {
        let lr = line.split(separator: " ")
        leftList.append(Int(lr[0])!)
        rightList.append(Int(lr[1])!)
    }
    return (leftList, rightList)
}

let (leftList, rightList) = readInput(filePath: CommandLine.arguments[1])
var counts: [Int: Int] = [:]
for n in rightList {
    counts[n, default: 0] += 1
}
print(leftList.reduce(0, { sum, n in sum + n * counts[n, default: 0] }))