AUST Carnival 1.0 A / CRT

/***
 created: 2023-02-06-15.59.28
***/

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template<typename U> using ordered_set=tree<U, null_type,less<U>,rb_tree_tag,tree_order_statistics_node_update>;
#define ll long long
#define all(we) we.begin(),we.end()
#define test int tt; cin>>tt; for(int cs=1;cs<=tt;cs++)
#define nl '\n'
#define ll long long int
#define pll pair<ll, ll>
ll egcd(ll a, ll b, ll& x, ll& y){
    if(!b) {y = 0, x = 1; return a;}
    ll g = egcd(b, a % b, y, x);
    y -= ((a / b) * x);
    return g;
}

pll GeneralCRT(pll a, pll b){
    if(a.second < b.second) swap(a, b);
    ///a.first=mod,a.second=rem
    ll x, y; egcd(a.second, b.second, x, y);
    ll g = a.second * x + b.second * y;
    ll l = a.second / g * b.second;
    if((b.first - a.first) % g) {return {-1, -1};} // No Solution
    ll c = (b.first - a.first) % b.second;
    c = (c * x) % b.second;
    c = c / g * a.second;
    c += a.first;
    if(c < 0) {c += l;}
    return {c, l};
}


int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    ll n,m,i,j,k,l;

    cin>>n;

    vector<pll>x(n);

    for(i=0;i<n;i++)
    {
        cin>>x[i].second>>x[i].first;
    }

    pll y=x[0];

    for(i=1;i<n;i++)
    {
        y=GeneralCRT(x[i],y);
    }

    cout<<y.first<<nl;


    return 0;
}