/*
 * Solution Template for Composing Pyramids
 * 
 * Australian Informatics Olympiad 2022
 * 
 * This file is provided to assist with reading and writing of the input
 * files for the problem. You may modify this file however you wish, or
 * you may choose not to use this file at all.
 */

#include <stdio.h>

/* N is the number of keys in the sequence. */
int N;

/* P contains the sequence of keys. */
int P[100005];

int answer;

int main(void) {
    FILE *input_file;
    FILE *output_file;
    int i;

    /* Open the input and output files. */
    input_file = fopen("compin.txt", "r");
    output_file = fopen("compout.txt", "w");

    /* Read the value of N. */
    fscanf(input_file, "%d", &N);

    /* Read the sequence of keys. */
    for (i = 0; i < N; i++) {
        fscanf(input_file, "%d", &P[i]);
    }

    /*
     * TODO: This is where you should compute your solution. Store the minimum
     * number of keys you need to remove from the sequence into the variable
     * answer.
     */

    /* Write the answer to the output file. */
    fprintf(output_file, "%d\n", answer);

    /* Finally, close the input/output files. */
    fclose(input_file);
    fclose(output_file);

    return 0;
}