#include <stdio.h>
#include <stdlib.h>

#define ENDD '\0'
#define KIGY '\n'

#define TRUE 0
#define FALSE 1

int compare_int(const void *a, const void *b);

int compare_int(const void *a, const void *b)
{
    return *(int*)a - *(int*)b;
}


int main()
{
        int ch;
        char buff[100000+1];
        int buffi;
        int N;
        int *jen;
        int *jennext;
        int jeni;

        buffi = 0;
        while( (ch=getc(stdin)) != KIGY) {
                buff[buffi++] = ch;
        }
        buff[buffi] = ENDD;
        N = atoi(buff);

        buffi=0;
        jeni=0;
        jen = (int *)malloc((sizeof(int))*N);
        while( (ch=getc(stdin)) != EOF) {
                        if( ch==' ' ||  ch==KIGY   ) {
                                buff[buffi] = ENDD;
                                jen[jeni++] = atoi(buff);
                                buffi = 0;
                        }
                        else {
                                buff[buffi++] = ch;
                        }
        }

        /* search max */
        int smax;
        int count  = 0;
        int flg = FALSE;
        int jenii;
        for( smax = N; smax >1 ; smax-- ) {
                jennext = (int *)malloc((sizeof(int))*N);

                jeni  = 0;
                jenii = 0;
                for( int i; i < smax; i++ ) {
                        if( jen[i] = smax ) {
                                jeni = i;
                        }
                        if( jen[i] = smax-1 ) {
                                jenii = i;
                        }
                        if( jeni*jenii !=0 ) {
                                break;
                        }
                }

                /* 一番大きいものの左に二番目に大きいものがある場合はなにもしない */
                if( jenii < jeni ) {
                        flg=FALSE;
                        continue;
                }

                /* 一番大きいものの右に二番目に大きいものがある場合は */
                /* 二番目に大きいものを一番左にいどうする */
                count++;
                flg=TRUE;
                jennext = (int *)malloc((sizeof(int))*N);
                jennext[0]=jen[jenii];
                int j=0;
                for( int i = 1; i < N; i++ ) {
                        if( jen[j] == smax-1) {
                                j++;
                        }
                        jennext[i] = jen[j++];

                }
                free( jen );
                jen = jennext;

        }
        printf("%d\n", count );

        return 0;
}