#include <bits/stdc++.h>
#define x first
#define y second
using namespace std;
using ull=unsigned long long;
using ll=long long;
using pii=pair<int,int>;
using vi=vector<int>;
using vl=vector<ll>;
#define pb push_back
#define all(a) begin(a),end(a)
#define sz(a) (int)(a).size()

const int N=500010,MOD=1e9+7,M=1<<19;
const char en='\n';
const ll LLINF=1ll<<60;

ull modadd(ull a,ull b,ull mod)
{
	if (a+b>=mod) return a+b-mod;
	return a+b;
}

ull modsub(ull a,ull b,ull mod)
{
	if (a>=b) return a-b;
	return a+mod-b;
}

ull modmul(ull a,ull b,ull M)
{
	ll ret = a * b - M * ull(1.L / M * a * b);
	return ret + M * (ret < 0) - M * (ret >= (ll) M);
}

ull modpow(ull b,ull e,ull mod)
{
	ull ans=1;
	for (;e;b=modmul(b,b,mod),e/=2) if (e&1) ans=modmul(ans,b,mod);
	return ans;
}

ull modinv(ull a,ull mod)
{
	return modpow(a,mod-2,mod);
}

bool isPrime(ull n)
{
	if (n<2 || n%6%4!=1) return (n|1)==3;
	ull A[]={2,325,9375,28178,450775,9780504,1795265022};
	ull s=__builtin_ctzll(n-1),d=n>>s;
	for (ull a: A)
	{
		ull p=modpow(a%n,d,n),i=s;
		while (p!=1 && p!=n-1 && a%n && i--) p=modmul(p,p,n);
		if (p!=n-1 && i!=s) return 0;
	}
	return 1;
}

int n,p[N],q[N];
ull v1[N],v2[N],pr1[N],pr2[N];
vector<pair<pii,int>> qu[N];
vi app[N];
int seg[M*2+10];

void upd(int i,int x)
{
	for (i+=M;i;i/=2) seg[i]+=x;
}

int ge(int l,int r,int lo=0,int hi=M,int i=1)
{
	if (lo>=l && hi<=r) return seg[i];
	if (lo>=r || hi<=l) return 0;
	int mid=(lo+hi)/2;
	return ge(l,r,lo,mid,i*2)+ge(l,r,mid,hi,i*2+1);
}

vector<ull> vals;

int toInd(ull x)
{
	return lower_bound(all(vals),x)-vals.begin();
}

pii toInd(pair<ull,ull> x)
{
	return {toInd(x.x),toInd(x.y)};
}

int main()
{
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	mt19937_64 rng(3892);
	uniform_int_distribution<ull> dist(1e18,2e18);
	ull p1=dist(rng);
	while (!isPrime(p1)) p1=dist(rng);
	ull p2=dist(rng);
	while (!isPrime(p2)) p2=dist(rng);
	ull maxdif=1e10;
	vals.pb(0);
	vals.pb(p1);
	vals.pb(p2);
	cin>>n;
	for (int i=0;i<n;++i)
	{
		cin>>p[i]>>q[i];
		v1[i]=modmul(p[i],modinv(q[i],p1),p1);
		v2[i]=modmul(p[i],modinv(q[i],p2),p2);
		pr1[i+1]=modadd(pr1[i],v1[i],p1);
		pr2[i+1]=modadd(pr2[i],v2[i],p2);
		vals.pb(pr1[i+1]);
		vals.pb(pr2[i+1]);
		vals.pb(modsub(pr1[i+1],maxdif,p1));
		vals.pb(modsub(pr2[i+1],maxdif,p2));
	}
	sort(all(vals));
	vals.erase(unique(all(vals)),vals.end());
	for (int i=0;i<=n;++i) app[toInd(pr1[i])].pb(toInd(pr2[i]));
	for (int i=1;i<=n;++i)
	{
		vector<pair<ull,ull>> i1,i2;
		ull x=pr1[i];
		if (x>=maxdif)
		{
			i1.pb({x-maxdif,x});
		}
		else
		{
			i1.pb({x+p1-maxdif,p1});
			i1.pb({0,x});
		}
		x=pr2[i];
		if (x>=maxdif)
		{
			i2.pb({x-maxdif,x});
		}
		else
		{
			i2.pb({x+p2-maxdif,p2});
			i2.pb({0,x});
		}
		for (auto x: i1)
		{
			for (auto y: i2) qu[toInd(x.y)].pb({toInd(y),1});
			for (auto y: i2) qu[toInd(x.x)].pb({toInd(y),-1});
		}
	}
	ll an=0;
	for (int i=0;i<=(int)vals.size();++i)
	{
		for (auto x: qu[i]) an+=x.y*ge(x.x.x,x.x.y);
		for (auto x: app[i]) upd(x,1);
	}
	cout<<an<<en;
}