include<bits/stdc++.h>

using namespace std;
string hieu(string a,string b){
while(a.size()<b.size()){
a='0'+a;
}
while(b.size()<a.size()){
b='0'+b;
}
int count;
for(int i=0;i<=a.size()-1;i++){
if(a[i]<b[i]){ swap(a,b); count=1; break; } else if(a[i]>b[i]){
break;
}
}
int carry=0;
string kq="";
for(int i=a.size()-1;i>=0;i--){
int tru=(a[i]-'0')-(b[i]-'0')-carry;
if(tru<0){
tru+=10;
carry=1;
}
else{
carry=0;
}
kq=char(tru+'0')+kq;
}
int index=0;
string ketqua=kq;
while(kq[index]=='0' && ketqua.size()>=2){
ketqua.erase(0,1);
index++;
}
if(count==1){
ketqua='-'+ketqua;
}
return ketqua;
}
int main(){
string m,n;
cin>>m>>n;
cout<<hieu(m,n);
}