//没加return，找了一个小时，擦了

include [HTML_REMOVED]

include [HTML_REMOVED]

using namespace std;
vector[HTML_REMOVED]c;
int x=0;
void add(vector[HTML_REMOVED] &a , vector[HTML_REMOVED] &b)
{
if(a.size() < b.size())
{
x=1;
return add(b,a);//要加return要加return要加return
}
else if(a.size() == b.size())
{
for(int i=a.size() - 1;i >= 0;i–)
{
if(a[i] > b[i])break;
if(a[i] == b[i])continue;
if(a[i] < b[i])
{
x=1;
return add(b,a);//要加return要加return要加return
}
}
}

int t=0;
for(int i=0;i<a.size();i++)
{
    t = a[i] - t;
    if(i < b.size())
    {
        t -= b[i];
    }
    c.push_back((t+10)%10);
    if(t<0)t = 1;
    else t = 0;
}
while(c.size() > 1 && c.back() == 0)c.pop_back();

}

int main()
{
string a,b;
cin >> a >> b;
vector[HTML_REMOVED] aa,bb;
for(int i=a.size() - 1;i>=0;i–)
{
aa.push_back(a[i] - ‘0’);
}
for(int i=b.size() - 1;i>=0;i–)
{
bb.push_back(b[i] - ‘0’);
}

add(aa,bb);
if(x == 1)cout << '-';
for(int i=c.size() - 1;i>=0;i--)
{
    cout << c[i];
}
return 0;

}