poj2665

#include <stdio.h>

int main(int argc, char* argv[])
{
 
 int length,many;
 int i;
 int start,end;
 int sum=0;

 scanf("%d %d",&length,&many);

 while(length !=0 && many != 0)
 {
  length += 1;

  for(i=0;i<many;i++)
  {
   scanf("%d %d",&start,&end);
   length -= (end-start)+1;
  }

  printf("%d/n",length);

  scanf("%d %d",&length,&many);

 }

 return 0;

}