#include <stdio.h>

#define IN "scmax.in"
#define OUT "scmax.out"
#define NMAX 100000

static unsigned long A[NMAX + 1];
static int S[NMAX + 1][NMAX + 1];

int main(void)
{
    int n, i, j;

    freopen(IN, "r", stdin);
    freopen(OUT, "w", stdout);

    scanf("%d", &n);

    for (i = 1; i <= n; i++) {
        scanf("%lu", &A[i]);
        S[i][0] = 0;
        S[0][i] = 0;
    }

    for (i = 1; i <= n; i++) {
        for (j = 1; j <= n; j++) {
            if (A[j] > A[i] && j > i)
                S[i][j] = S[i - 1][j - 1] + 1;
            else if (S[i - 1][j] > S[i][j - 1])
                S[i][j] = S[i - 1][j];
            else
                S[i][j] = S[i][j - 1];
        }
    }

    printf("%d\n", S[n][n]);


    return 0;
}