#define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES

#include <bits/stdc++.h>
using namespace std;
using i8  = int8_t;  using u8  = uint8_t;
using i16 = int16_t; using u16 = uint16_t;
using i32 = int32_t; using u32 = uint32_t;
using i64 = int64_t; using u64 = uint64_t;
using f32 = float_t; using f64 = double_t;
using usize = size_t;using str = string;
template <class T> using vec = vector<T>;
#define times(n, i) for (i32 i = 0; i < (n); i++)
#define range(n, m, i) for (i32 i = (n); i < (m); i++)
#define upto(n, m, i) for (i32 i = (n); i <= (m); i++)
#define downto(n, m, i) for (i32 i = (n); i >= (m); i--)
#define foreach(xs, x) for (auto &x : (xs))
#define all(xs) (xs).begin(), (xs).end()
#define sortall(xs) sort(all(xs))
#define reverseall(xs) reverse(all(xs))
#define uniqueall(xs) (xs).erase(unique(all(xs)), (xs).end())
#define maximum(xs) *max_element(all(xs))
#define minimum(xs) *min_element(all(xs))
const i64 MOD = 1000000007;

i32 main()
{
    i32 n;
    cin >> n;
    vec<i32> a(n);
    vec<i32> v(n);
    times(n, i) {
        cin >> a[i]; a[i]--;
        v[i] = i;
    }
    i32 cnt = 0;
    downto(n-2, 0, i) {
        usize xi = -1, yi = -1;
        times(n, j) {
            if (a[j] == i)
                xi = j;
            if (a[j] == i+1)
                yi = j;
            if (xi > -1 && yi > -1)
                break;
        }
        if (xi < yi)
            continue;
        a.erase(a.begin() + xi);
        a.insert(a.begin(), i);
        cnt++;
    }
    cout << cnt << endl;
    return 0;
}