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

void greska();

int main(int argc, char **argv)
{
    if(argc != 5)
        greska();
    
    FILE *ulaz = fopen(argv[4], "r");
    if(ulaz == NULL)
        greska();
 
    FILE *izlaz = fopen("izlaz.txt", "w");
    if(izlaz == NULL)
        greska();
    
    int a = atoi(argv[1]);
    int b = atoi(argv[2]);
    int n = atoi(argv[3]);
    
    if(n <= 0 || a <= 0 || b <= 0)
        greska();
    
    int i;
    int broj;
    int count = 0;
    
    for(i = 0; i < n; i++)
    {
        fscanf(ulaz, "%d", &broj);
        if(broj < (a+b)/2.0)
            count++;
    }
    
    fprintf(izlaz, "%d", count);
    
    fclose(ulaz);
    fclose(izlaz);
    return 0;
}

void greska()
{
    fprintf(stderr, "-1");
    exit(EXIT_FAILURE);
}