/*
  MorbidZ rule
*/

#include<stdio.h>




int main(){
    
    
    int n,m,r,s;
    scanf("%d %d",&n,&m);
    for(int i=0;i<n;i++)scanf("%d %d",&r,&s);    
    printf("%d",m-n+1);
 
    
    return 0;
}