#include <vector>
#include <iostream>
#include <fstream>
#include <cstddef>
#include <string>

namespace {

size_t Merge(std::vector<size_t>& a, size_t i, size_t chunk_size, std::vector<size_t>& tmp) {
     std::vector<size_t>::iterator a1 = a.begin() + i;
     size_t l1 = chunk_size;
     std::vector<size_t>::iterator a2 = a1 + l1;
     size_t l2 = (a.size() > i + chunk_size * 2) ? chunk_size : a.size() - i - chunk_size;

     tmp.clear();
     size_t res = 0;

     for (size_t i1 = 0, i2 = 0; i1 != l1 || i2 != l2; ) {
          if (i1 == l1) {
               tmp.push_back(a2[i2++]);
          } else if (i2 == l2) {
               tmp.push_back(a1[i1++]);
          } else if (a1[i1] < a2[i2]) {
               tmp.push_back(a1[i1++]);
          } else if (a2[i2] < a1[i1]) {
               tmp.push_back(a2[i2++]);
               res += l1 - i1;
          } else {
               std::cerr << "Oops" << std::endl;
          }
     }

     for (size_t di = 0; di < tmp.size(); ++di)
          a[i + di] = tmp[di];

     return res;
}

size_t CountCross(std::vector<size_t>& a) {
     size_t res = 0;
     std::vector<size_t> tmp(a.size());

     for (size_t chunk_size = 1; chunk_size < a.size(); chunk_size *= 2)
          for (size_t i = 0; i + chunk_size < a.size(); i += chunk_size * 2)
               res += Merge(a, i, chunk_size, tmp);

     return res;
}

}

int N;
int x;
int main(int argc, char **argv) {
        scanf("%d",&N);
        std::vector<size_t> M;
        for(int i = 0; i < N; i++){
                scanf("%d",&x);
                M.push_back(x);
        }
     std::cout << CountCross(M) << std::endl;
}