/*
TASK:psort
LANG:C
*/

#include <stdio.h>
#define MAX 50002
FILE *in; FILE *out;
int a[MAX];
int plc[MAX];
int n, m;


int main(void)
{
int i, c;
int ans;

//in = fopen("psort.in", "rt"); out = fopen("psort.out", "wt");
in = stdin; out = stdout;

for (i=0; i<MAX; i++) {a[i] = 0; plc[i] = 0;}

fscanf(in, "%d", &n);
for (i=0; i<n; i++)
    {
    fscanf(in, "%d", &a[i]);
    plc[a[i]] = i;
    }


ans = n-1; c = 0;
for (i=1; i<n; i++)
   {
   if (plc[i] < plc[i+1]) c++;
   }
ans -= c;
fprintf(out, "%d\n", ans);


fclose(in); fclose(out);

return 0;
}
