#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define rep(i,a,b) for(int i=a;i<=b;i++)
#define per(i,a,b) for(int i=a;i>=b;i--)
const int T = 4e6 + 5, N = 2e5 + 5;
int sz, n, s[T], ls[T], rs[T];
ll r, r1, r2;
int ins(int L, int R, int w) {
	s[++sz] = 1;
	if (L == R) return sz;
	int m = L + R >> 1, nw = sz;
	w <= m ? ls[nw] = ins(L, m, w) : rs[nw] = ins(m + 1, R, w);
	return nw;
}
int merge(int u, int v) {
	if (!u || !v) return u | v;
	s[u] += s[v];
	r1 += 1ll * s[ls[u]] * s[rs[v]];
	r2 += 1ll * s[rs[u]] * s[ls[v]];
	ls[u] = merge(ls[u], ls[v]);
	rs[u] = merge(rs[u], rs[v]);
	return u;
}
int build() {
	int w;
	cin >> w;
	if (w) return ins(1, n, w);
	int ls = build(), rs = build();
	r1 = r2 = 0;
	int c = merge(ls, rs);
	r += min(r1, r2);
	return c;
}
signed main() {
	cin >> n;
	build();
	cout << r;
	return 0;
}