P2152

唐

#include<bits/stdc++.h>
#define U(i,l,r) for(int i(l);i<=r;++i)
#define D(i,r,l) for(int i(r);i>=l;--i)
#define Huge_Int vector<long long>
#define BASE (1000000000ll)
using namespace std;
Huge_Int Huge_Read(){
	static char c[100005];
	Huge_Int t;scanf("%s",c);int l(strlen(c)-1);
	for(;l>=8;l-=9)	{
		t.push_back(0);long long &x(t.back());
		U(i,l-8,l) x=x*10+(c[i]^48);
	}
	if(~l)	{
		t.push_back(0);long long &x(t.back());
		U(i,0,l) x=x*10+(c[i]^48);
	}
	return t;
}
void pt(Huge_Int a){
	printf("%lld",a[a.size()-1]);
	D(i,(int)a.size()-2,0) printf("%09lld",a[i]);
}
Huge_Int operator*(Huge_Int a,int b){
	int temp(0);
	U(i,0,(int)a.size()-1){
		if((a[i]=a[i]*b+temp,temp=0,a[i])>=BASE){
			if(i==a.size()-1) a.push_back(0);
			temp=a[i]/BASE,a[i]%=BASE;
		}
	}
	return a;
}
Huge_Int operator-(Huge_Int a,Huge_Int b){
	U(i,0,b.size()-1)if((a[i]-=b[i])<0) a[i]+=BASE,--a[i+1];
	while(a.size()>1&&!a.back()) a.pop_back();
	return a;
}
Huge_Int operator/(Huge_Int a,int b){
	int temp(0);
	D(i,a.size()-1,0) a[i]+=temp*BASE,temp=a[i]%b,a[i]/=b;
	while(a.size()>1&&!a[a.size()-1]) a.pop_back();
	return a;
}
bool operator<(Huge_Int a,Huge_Int b){
	if(a.size()>b.size()) return false;
	if(a.size()<b.size()) return true;
	D(i,a.size()-1,0){
		if(a[i]>b[i]) return false;
		else if(a[i]<b[i]) return true;
	}
	return false;
}
Huge_Int gcd(Huge_Int a,Huge_Int b){
	int tims(0);if(a<b) swap(a,b);
	while(!(a[0]&1)&&!(b[0]&1)) a=a/2,b=b/2,++tims;
	while(!(a==b)){
		int t1(a[0]&1),t2(b[0]&1);
		!t1?a=a/2:(!t2?b=b/2:a=a-b);
		if(a<b) swap(a,b);
	}
	while(tims--) a=a*2;
	return a;
}
signed main(){ 
	return pt(gcd(Huge_Read(),Huge_Read())),0;
}