#include<iostream> #include<vector> using namespace std; int main(){ string s; cin>>s; vector<int> a,b; for(int i=s.size()-1;i>-1;i--){ a.push_back(s[i]-'0'); } cin>>s; for(int j=s.size()-1;j>-1;j--){ b.push_back(s[j]-'0'); } int sam=0; vector<int> d(a.size(),0); for(int i=0;i<a.size()||b[i];i++){ if(i>=b.size()){ b[i]=0; } if(a[i]<b[i]&&i+1<a.size()){ a[i]+=10; a[i+1]-=1; } d[i]=a[i]-b[i]; } while(d.size()>1&&d.back()==0){ d.pop_back(); } for(int i=d.size()-1;i>=0;i--){ cout<<d[i]; } return 0; }