#include<iostream>#include<set>#include<cstdio>#include<cstring>#include<stdlib.h>#include<algorithm>using namespace std;enum { SIZ = 104,};struct Node { unsigned long long up, dn; bool operator < (const Node&o)const{ return dn < o.dn; } void add(const Node &o);};int gcd(unsigned long long a, unsigned long long b){ unsigned long long t; if( a < b){ t = a, a = b, b = t; } while(b > 0){ t = a % b; a = b; b = t; } return a;}void Node::add(const Node &o) { if (o.up <= 0) return; if (up <= 0){ up = o.up; dn = o.dn; return; } if (dn == o.dn){ up += o.up; } else { unsigned long long t = gcd(dn, o.dn); t = dn * o.dn / t; up = t/dn*up + t/o.dn*o.up; dn = t; t = gcd(dn, up); dn /= t; up /= t; }}int num;Node tre[SIZ];Node sum[SIZ];void fun(){ if (sum[num-1].up > sum[num-1].dn){ printf("-1n"); return; } unsigned long long r = 0; unsigned long long carry = 0; for (int i=num-1; i>0; --i){ carry += tre[i].up; unsigned long long u = tre[i-1].dn * (sum[i-1].dn - sum[i-1].up) / sum[i-1].dn; unsigned long long t = carry / u; r += t * tre[i-1].dn; carry %= u; if (carry ==0){ break; } } if (carry){ r += carry + tre[0].up; } if (num == 1) r = tre[0].up; printf("%llun", r);}void readIn(){ scanf("%d ", &num); for (int i=0; i<num; ++i){ scanf("%llu%llu ", &tre[i].up, &tre[i].dn); } sort(tre, tre+num); for (int i=0; i<num; ++i){ sum[i].up = sum[i].dn = 0; sum[i].add(tre[i]); if (i){ sum[i].add (sum[i-1]); } }}int main(){ int tst; scanf("%d ", &tst); while(tst--){ readIn(); fun(); } return 0;}
