c언어에서 "Unhandled exception~: Access Violation." 오류

아무리고민해봐도 왜 이오류가나오는지 이유를 잘모르겠습니다;



도와주세요 ㅠㅠ





#include <stdio.h>
#include <Windows.h>
#include <math.h>


int main(void){
unsigned int time_start;
unsigned int time_end;
unsigned int time_true;







  int *count;
  int c,d,e,i,j,t,k,n,m,z,answer = 0;

  int a[25000];
  int b[25000];

  FILE * in;
  FILE * out;
  in = fopen("C:\\input.txt", "r");
  out = fopen("C:\\output.txt", "w");

  time_start = GetTickCount();

  fscanf(in, "%d %d", &n, &k);
  count = (int*)calloc(n, sizeof(int));



  for(c=0, d=0 ; c,d<k ; c++,d++){
   fscanf(in, "%d %d" , &a[c], &b[d]);
  }


 
for(e=0; e<k ;e++){
  z=a[e], m=b[e];
     for(z; z <= m ; z++){
   count[z]++;
  }
   }

  

   for(i=0; i<n-1 ; i++){
    for(j=i+1; j<n; j++){
   
   if(count[i] > count[j]) {
     t = count[i];
     count [i] = count [j];
     count [j] = t;
   }
    }
   }
 
   answer = n/2+1;

   fprintf(out, "%d", &count[answer]);
   free(count);

time_end = GetTickCount();
time_true = time_end - time_start;
printf("\n Finishing in : %d \n", time_true);
return 0;}