tijie

#include <bits/stdc++.h>
using namespace std;

int a[10010],b[10010],c[10010];
bool cmp(string s1,string s2){
    if(s1.size() != s2.size()){
        return s1.size() < s2.size();
    }else{
        return s1 < s2;
    }
}

int main(){
	string s1,s2;
	cin >> s1 >> s2;
    if(cmp(s1,s2)){
        cout << '-';
        swap(s1,s2);
    }
	int l1 = s1.size();
	int l2 = s2.size();
	int idx = max(l1,l2)-1;
	for(int i=0;i<l1;i++) a[i] = s1[l1-1-i] - '0';
	for(int i=0;i<l2;i++) b[i] = s2[l2-1-i] - '0';
	for(int i=0;i<=idx;i++){
		c[i] += a[i] - b[i];
        if(c[i] < 0){
            c[i] += 10;
    		c[i+1] -= 1;	
        }
	} 
    while(!c[idx] && idx) idx--;
	for(int i=idx;i>=0;i--){
		cout << c[i] ; 
	} 
	return 0;
}