哪位DALAO帮忙看一下为什么编译过不了

#include<cstdio>
#include<algorithm>
#include<iostream>
using namespace std;

long int i,j,n;

long long x,y,ans=0;

inline long long read()
{
    long long k=0,f=1;char ch=getchar();
    while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
    while(ch>='0'&&ch<='9'){k=k*10+ch-'0';ch=getchar();}
    return k*f;
}
inline void write(long long x)
{
    if(x<0)x=-x,putchar('-');
    if(x>9)write(x/10);putchar(x%10+'0');
}

struct node
{
    int l,r;
}a[100001];

int main(){
	n=read();
	for(i=1;i<=n;i++){
		a[i].l=read();
		a[i].r=read();
	}
	sort(a+1,a+n+1);
	for(i=1;i<=n;i++){
		if(a[i].l>y){
			ans+=a[i].r-a[i].l+1;
			y=a[i].r;
		}
		else{
			if(a[i].r>y){
				ans+=a[i].r-y+1;
				y=a[i].r;
			}
		}
	}
	printf("%lld",ans);
	return 0;
}