"use strict";
exports.__esModule = true;
var fs = require("fs");
var BinaryIndexedTree = function (n) {
    var data = Array(n).fill(0);
    var add = function (p, x) {
        p++;
        var n = data.length;
        while (p <= n) {
            data[p - 1] += x;
            p += p & -p;
        }
    };
    var sum = function (p) {
        var res = 0;
        while (p > 0) {
            res += data[p - 1];
            p -= p & -p;
        }
        return res;
    };
    var rangeSum = function (l, r) {
        return sum(r) - sum(l);
    };
    return { add: add, sum: sum, rangeSum: rangeSum };
};
var main = function (args) {
    var input = args.trim().split("\n");
    var n = +input.shift();
    var p = input.shift().split(" ").map(function (x) { return +x; });
    var bit = BinaryIndexedTree(n + 1);
    var ans = 0;
    p.forEach(function (x) {
        ans += bit.rangeSum(x + 1, n + 1);
        bit.add(x, 1);
    });
    console.log(ans);
};
main(fs.readFileSync('/dev/stdin', 'utf8'));