最后三个点出错，三个点时而T时而WA（还轮了一圈）

#include<iostream>
#include<cstdio>
#include<cmath>
#include<string>
#include<cstring>
#include<algorithm>
#include<cassert>
#include<stack>
#include<queue>
#include<vector>
#include<map>
#include<cstdlib>
using namespace std;
#define ll long long
#define ull unsigned long long
ll read()
{
	ll now=0,nev=1; 
	char c=getchar();
	while(c<'0' || c>'9') 
	{ 
		if(c=='-') 
			nev=-1; 
		c=getchar();
	}
	while(c>='0' && c<='9') 
	{ 
		now=(now<<1)+(now<<3)+(c&15); 
		c=getchar(); 
	}
	return now*nev;
}
const int MAXN=1e5+10;
ll n;
ll a[MAXN],b[MAXN];
ll x,y;
ll exgcd(ll a,ll b,ll &x,ll &y)
{
	if(b==0)
	{
		x=1;
		y=0;
		return a;
	}
	int d=exgcd(b,a%b,y,x);
	y-=(a/b*x);
	return d;
}
ll slowcheng(ll a,ll b,ll mod)
{
	ll res=0;
	a=(a%mod+mod)%mod;
	b=(b%mod+mod)%mod;
	while(b)
	{
		if(b&1)
			res=(res+a)%mod;
		a=(a+a)%mod;
		b>>=1;
	}
	return (res+mod)%mod;
}
ll EXCRT()
{
	ll M=a[1];
	ll ans=b[1];
	for(int i=2;i<=n;i++)
	{
		ll c=((b[i]-ans)%a[i]+a[i])%a[i];
		ll d=exgcd(M,a[i],x,y);
		ll p=a[i]/d;
		x=slowcheng(x,c/d,p);
		ans+=x*M;
		M*=p;
		ans=(ans%M+M)%M;
	}
	return ans;
}
int main()
{
	n=read();
	for(int i=1;i<=n;i++)
		a[i]=read(),b[i]=read();
	printf("%lld",EXCRT());
	return 0;
}