#include <bits/stdc++.h>

using namespace std;

// 判断A>=B是否成立
bool cmp(vector<int>&A, vector<int>&B){
    if(A.size()==B.size()){
        for(int i=0; i<A.size(); ++i)
            if(A[i]>B[i]) return true;
            else if(A[i]<B[i]) return false;
            else continue;
    }
    return A.size()>=B.size();
}


// 计算A-B, 当A>=B
vector<int> sub(vector<int>& A, vector<int>& B){
    int i=A.size()-1;
    int j=B.size()-1;
    int c=0;
    vector<int> C;
    while(i>=0 || c){
        int va=A[i]+c;
        int vb=j>=0?B[j]:0;
        int v;
        if(va<vb){
            v=va+10-vb;
            c=-1;
        }
        else{
            v=va-vb;
            c=0;
        }
        C.push_back(v);
        --i;
        --j;
    }

    // 检查前导0
    while(C.size()>1 && !C.back()) C.pop_back();
    if(C.size()>1)
        reverse(C.begin(), C.end());
    return C;
}

int main(){
    string a, b;
    cin>>a>>b;

    vector<int> A, B;
    for(int i=0; i<a.size(); ++i) A.push_back(a[i]-'0');
    for(int i=0; i<b.size(); ++i) B.push_back(b[i]-'0');

    vector<int> C;
    if(cmp(A, B)){
        C=sub(A, B);
    }
    else{
        C=sub(B, A);
        cout<<"-";
    }
    for(auto &c: C) cout<<c;

    return 0;
}