#include #include #include #include #include #include const int INF=0x3f3f3f3f; const int N=1e5+10; using namespace std; string a,b; int a1[N],b1[N],c1[N],lena,lenb,lenc; int main(){ cin>>a>>b; lena=a.size(); lenb=b.size(); if(lena<lenb||(lena == lenb&&a<b)) { swap(lena,lenb); swap(a,b); cout<<"-"; } for(int i=0;i<lena;i++) { a1[i]=a[lena-i-1]-'0'; } for(int i=0;i<lenb;i++) b1[i]=b[lenb-i-1]-'0'; lenc =lena; for(int i =0;i<lenc;i++) { c1[i]=a1[i]-b1[i]; if(c1[i]<0) { a1[i+1]--; c1[i] += 10; } } while(c1[lenc]==0&&lenc>0) lenc--;

for(int i=lenc;i>=0;i--)
	cout<<c1[i];
return 0;

}