#ifndef POINTER05_H_
#define POINTER05_H_

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cassert>

int find_length (int *head, int *tail);

int main ()
{
    int n;
    scanf("%d", &n);

    int *arr = (int *) malloc(sizeof(int[200'000]));
    for (int i = 0, l, r; i < n; i++)
    {
        scanf("%d", &l);
        r = find_length(&arr[0], &arr[l - 1]);
        if (l != r)
        {
            printf("peach found bug at #%d: expect %d but get %d\n", i, l, r);
            return 0;
        }
    }

    printf("peach check: ok\n");
}
#endif // POINTER05_H_