//chu是除数,yu是余数 //注意只适用于除数两两互质 #include<iostream> #include<queue> using namespace std; int extended_euclid(int a, int b, int &x, int &y) { int d; if(b == 0) {x = 1; y = 0; return a;} d = extended_euclid(b, a % b, y, x); y -= a / b * x; return d; } int chinese_remainder(int b[], int w[], int len) { int i, d, x, y, m, n, ret; ret = 0; n = 1; for(i=0; i < len ;i++) n *= w[i]; for(i=0; i < len ;i++) { m = n / w[i]; d = extended_euclid(w[i], m, x, y); ret = (ret + y*m*b[i]) % n; } return (n + ret%n) % n; } int yu[100],chu[100]; int main() { int n; while(scanf("%d",&n)!=EOF) { for(int i=0;i<n;i++) { cin>>chu[i]>>yu[i]; } int ans=chinese_remainder(yu,chu,n); printf("%d/n",ans); } }