#include<bits/stdc++.h>
#define rep(x,y,z) for(ull x=y;x<=z;x++)
#define drep(x,y,z) for(int x=y;x>=z;x--)
#define ull unsigned long long
#define ll long long
using namespace std;
inline int read()
{
	int x=0;bool flag=1;char ch=getchar();
	while(ch<'0'||ch>'9') {if(ch=='-')flag=0;ch=getchar();}
	while(ch>='0'&&ch<='9') {x=(x<<3)+(x<<1)+ch-'0';ch=getchar();}
	if(flag) return x;
	return ~(x-1);
} 
inline void write(int x)
{
	if(x<0) {x=~(x-1);putchar('-');}
	if(x>9) write(x/10);
	putchar(x%10+'0');
}
////////////////////////
const ull N=1e18;
int nc;
struct G
{
    ull a;
    ull b;    
}n[21];
bool cmp(G x,G y){return x.a>y.a;}
int pd(ull x)
{
    int re=1;
    rep(i,2,nc)
    {
        if(x%n[i].a!=n[i].b) 
        {
            re=0;
            break;
        }
    }
    return re;
}
int main()
{
    freopen("ccyz.in","r",stdin);
	freopen("ccyz.out","w",stdout);
    nc=read();
    rep(i,1,nc) n[i].a=read(),n[i].b=read();
    sort(n+1,n+nc+1,cmp);
    rep(i,1,N/n[1].a)
    {
        if(pd(i*n[1].a+n[1].b))
        {
            cout<<i*n[1].a+n[1].b<<endl;
            break;
        }
    }
    return 0;
}